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SILENT SPRING, winner of 8 awards*, is the history making bestseller that 
stunned the world with its terrifying revelation about our contaminated planet. No science- 
fiction nightmare can equal the power of this authentic and chilling portrait of the un-seen 
destroyers which have already begun to change the shape of life as we know it. 

"Silent Spring is a devastating attack on human carelessness, greed and 
irresponsibility. It should be read by every American who does not want it to be the epitaph of 
a world not very far beyond us in time." 

— Saturday Review 

*Awards received by Rachel Carson for Si lent Spring: 

• The Schweitzer Medal (Animal Welfare Institute) 

• The Constance Lindsay Skinner Achievement Award for merit in the realm of books (Women's 
National Book Association) 

• Award for Distinguished Service (New England Outdoor Writers Association) 

• Conservation Award for 1962 (Rod and Gun Editors of Metropolitan Manhattan) 

• Conservationist of the Year (National Wildlife Federation) 

• 1963 Achievement Award (Albert Einstein College of Medicine — Women's Division) 

• Annual Founders Award (Isaak Walton League) 

• Citation (International and U.S. Councils of Women) 

Silent Spring 

( By Rachel Carson ) 

• "I recommend SILENT SPRING above all other books." — N. J. Berrill author of MAN'S 

• "Certain to be history-making in its influence upon thought and public policy all over the 
world." -Book-of-the-Month Club News 

• "Miss Carson is a scientist and is not given to tossing serious charges around carelessly. 
When she warns us, as she does with such a profound sense of urgency, we ought to 
take heed. SILENT SPRING may well be one of the great and lowering books of our time. 
This book is must reading for every responsible citizen." --Chicago Daily 

• "Miss Carson's cry of warning is timely. If our species cannot police itself against 
overpopulation, nuclear weapons and pollution, it may become extinct." -The New York 

• "A great woman has awakened the Nation by her forceful account of the dangers 
around us. We owe much to Rachel Carson." -Stewart L. Udall, Secretary of the Interior 

• "It is high time for people to know about these rapid changes in their environment, and 
to take an effective part in the battle that may shape the future of all life on earth." -The 
New York Times Book Review{front page} 

• "It should come as no surprise that the gifted author of THE SEA AROUN US can take 
another bra nch of science ... and bring it so sharply into focus that any intelligent 
layman can understand what she is talking about. Understand, yes, and shudder, for she 
has drawn a living portrait of what is happening to this balance of nature as decreed in 
the science of life — and what man is doing (and has done) to destroy it and create a 
science of death." -Virginia Kirkus Bulletin 


By Rachel Carson 




To Albert Schweitzer 
who said 

"Man has lost the capacity to foresee 
and to forestall. He will end by 
destroying the earth." 


i. Acknowledgments 

ii. Foreword 


A Fable for Tomorrow 


The Obligation to Endure 


Elixirs of Death 


Surface Waters and Underground Seas 


Realms of the Soil 


Earth's Green Mantle 


Needless Havoc 


And No Birds Sing 


Rivers of Death 


Indiscriminately from the Skies 

11. Beyond the Dreams of the Borgias 

12. The Human Price 

13. Through a Narrow Window 

14. One in Every Four 

15. Nature Fights Back 

16. The Rumblings of an Avalanche 

17. The Other Road 


IN A LETTER written in January 1958, Olga Owens Huckins told me of her own bitter 
experience of a small world made lifeless, and so brought my attention sharply back to a 
problem with which I had long been concerned. I then realized I must write this book. 
During the years since then I have received help and encouragement from so many people that 
it is not possible to name them all here. Those who have freely shared with me the fruits of 
many years' experience and study represent a wide variety of government agencies in this and 
other countries, many universities and research institutions, and many professions. To all of 
them I express my deepest thanks for time and thought so generously given. 
In addition my special gratitude goes to those who took time to read portions of the manuscript 
and to offer comment and criticism based on their own expert knowledge. Although the final 
responsibility for the accuracy and validity of the text is mine, I could not have completed the 
book without the generous help of these specialists: L. G. Bartholomew, M.D., of the Mayo 
Clinic, John J. Biesele of the University of Texas, A. W. A. Brown of the University of Western 
Ontario, Morton S. Biskind, M.D., of Westport, Connecticut, C. J. Briejer of the Plant Protection 
Service in Holland, Clarence Cottam of the Rob and Bessie Welder Wildlife Foundation, George 
Crile, Jr., M.D., of the Cleveland Clinic, Frank Egler of Norfolk, Connecticut, Malcolm M. 
Hargraves, M.D., of the Mayo Clinic, W. C. Hueper, M.D., of the National Cancer Institute, C. J. 
Kerswill of the Fisheries Research Board of Canada, Olaus Murie of the Wilderness Society, A. D. 
Pickett of the Canada Department of Agriculture, Thomas G. Scott of the Illinois Natural History 
Survey, Clarence Tarzwell of the Taft Sanitary Engineering Center, and George J. Wallace of 
Michigan State University. Every writer of a book based on many diverse facts owes much to 
the skill and helpfulness of librarians. I owe such a debt to many, but especially to Ida K. 
Johnston of the Department of the Interior Library and to Thelma Robinson of the Library of the 
National Institutes of Health. 

As my editor, Paul Brooks has given steadfast encouragement over the years and has 
cheerfully accommodated his plans to postponements and delays. For this, and for his skilled 
editorial judgment, I am everlastingly grateful. I have had capable and devoted assistance in the 
enormous task of library research from Dorothy Algire, Jeanne Davis, and Bette Haney Duff. 
And I could not possibly have completed the task, under circumstances sometimes difficult, 
except for the faithful help of my housekeeper, Ida Sprow. 

Finally, I must acknowledge our vast indebtedness to a host of people, many of them 
unknown to me personally, who have nevertheless made the writing of this book seem 
worthwhile. These are the people who first spoke out against the reckless and irresponsible 
poisoning of the world that man shares with all other creatures, and who are even now fighting 
the thousands of small battles that in the end will bring victory for sanity and common sense in 
our accommodation to the world that surrounds us. 



IN 1958, when Rachel Carson undertook to write the book that became Silent Spring, 
she was fifty years old. She had spent most of her professional life as a marine biologist and 
writer with the U.S. Fish and Wildlife Service. But now she was a world-famous author, thanks 
to the fabulous success of The Sea Around Us, published seven years before. Royalties from this 
book and its successor, The Edge of the Sea, had enabled her to devote full time to her own 
writing. To most authors this would seem like an ideal situation: an established reputation, 
freedom to choose one's own subject, publishers more than ready to contract for anything one 
wrote. It might have been assumed that her next book would be in a field that offered the same 
opportunities, the same joy in research, as did its predecessors. Indeed she had such projects in 
mind. But it was not to be. While working for the government, she and her scientific colleagues 
had become alarmed by the widespread use of DDT and other long-lasting poisons in so-called 
agricultural control programs. Immediately after the war, when these dangers had already been 
recognized, she had tried in vain to interest some magazine in an article on the subject. A 
decade later, when the spraying of pesticides and herbicides (some of them many ti mes as toxic 
as DDT) was causing wholesale destruction of wildlife and its habitat, and clearly endangering 
human life, she decided she had to speak out. Again she tried to interest the magazines in an 
article. Though by now she was a well-known writer, the magazine publishers, fearing to lose 
advertising, turned her down. For example, a manufacturer of canned baby food claimed that 
such an article would cause "unwarranted fear" to mothers who used his product. (The one 
exception was The New Yorker, which would later serialize parts of Silent Spring in advance of 
book publication.) So the only answer was to write a book— book publishers being free of 
advertising pressure. Miss Carson tried to find someone else to write it, but at last she decided 
that if it were to be done, she would have to do it herself. Many of her strongest admirers 
questioned whether she could write a salable book on such a dreary subject. She shared their 
doubts, but she went ahead because she had to. "There would be no peace for me," she wrote 
to a friend, "if I kept silent." 

Silent Spring was over four years in the making. It required a very different kind of 
research from her previous books. She could no longer recount the delights of the laboratories 
at Woods Hole or of the marine rock pools at low tide. Joy in the subject itself had to be 
replaced by a sense of almost religious dedication. And extraordinary courage: during the final 
years she was plagued with what she termed "a whole catalogue of illnesses." 
Also she knew very well that she would be attacked by the chemical industry. It was not simply 
that she was opposing indiscriminate use of poisons but— more fundamentally— that she had 
made clear the basic irresponsibility of an industrialized, technological society toward the 
natural world. When the attack did come, it was probably as bitter and unscrupulous as 
anything of the sort since the publication of Charles Darwin's Origin of Species a century before. 

Hundreds of thousands of dollars were spent by the chemical industry in an attempt to 
discredit the book and to malign the author— she was described as an ignorant and hysterical 
woman who wanted to turn the earth over to the insects. These attacks fortunately backfired 
by creating more publicity than the publisher possibly could have afforded. A major chemical 

company tried to stop publication on the grounds that Miss Carson had made a misstatement 
about one of their products. She hadn't, and publication proceeded on schedule. 
She herself was singularly unmoved by all this furor. 

Meanwhile, as a direct result of the message in Silent Spring, President Kennedy set up a 
special panel of his Science Advisory Committee to study the problem of pesticides. The panel's 
report, when it appeared some months later, was a complete vindication of her thesis. Rachel 
Carson was very modest about her accomplishment. As she wrote to a close friend when the 
manuscript was nearing completion: "The beauty of the living world I was trying to save has 
always been uppermost in my mind— that, and anger at the senseless, brutish things that were 
being done.... Now I can believe I have at least helped a little." In fact, her book helped to make 
ecology, which was an unfamiliar word in those days, one of the great popular causes of our 
time. It led to environmental legislation at every level of government. 

Twenty-five years after its original publication, Silent Spring has more than a historical 
interest. Such a book bridges the gulf between what C. P. Snow called "the two cultures." 
Rachel Carson was a realistic, well-trained scientist who possessed the insight and sensitivity of 
a poet. She had an emotional response to nature for which she did not apologize. The more she 
learned, the greater grew what she termed "the sense of wonder." So she succeeded in making 
a book about death a celebration of life. Rereading her book today, one is aware that its 
implications are far broader than the immediate crisis with which it dealt. By awaking us to a 
specific danger— the poisoning of the earth with chemicals— she has helped us to recognize 
many other ways (some little known in her time) in which mankind is degrading the quality of 
life on our planet. 

And Silent Spring will continue to remind us that in our over-organized and over- 
mechanized age, individual initiative and courage still count: change can be brought about, not 
through incitement to war or violent revolution, but rather by altering the direction of our 
thinking about the world we live in. 

1. A Fable for Tomorrow 

THERE WAS ONCE a town in the heart of America where all life seemed to live in 
harmony with its surroundings. The town lay in the midst of a checkerboard of prosperous 
farms, with fields of grain and hillsides of orchards where, in spring, white clouds of bloom 
drifted above the green fields. In autumn, oak and maple and birch set up a blaze of color that 
flamed and flickered across a backdrop of pines. Then foxes barked in the hills and deer silently 
crossed the fields, half hidden in the mists of the fall mornings. 

Along the roads, laurel, viburnum and alder, great ferns and wildflowers delighted the traveler's 
eye through much of the year. Even in winter the roadsides were places of beauty, where 
countless birds came to feed on the berries and on the seed heads of the dried weeds rising 
above the snow. The countryside was, in fact, famous for the abundance and variety of its bird 
life, and when the flood of migrants was pouring through in spring and fall people traveled from 
great distances to observe them. Others came to fish the streams, which flowed clear and cold 
out of the hills and contained shady pools where trout lay. So it had been from the days many 
years ago when the first settlers raised their houses, sank their wells, and built their barns. 
Then a strange blight crept over the area and everything began to change. Some evil spell had 
settled on the community: mysterious maladies swept the flocks of chickens; the cattle and 
sheep sickened and died. Everywhere was a shadow of death. The farmers spoke of much 
illness among their families. In the town the doctors had become more and more puzzled by 
new kinds of sickness appearing among their patients. There had been several sudden and 
unexplained deaths, not only among adults but even among children, who would be stricken 
suddenly while at play and die within a few hours. 

There was a strange stillness. The birds, for example— where had they gone? Many people 
spoke of them, puzzled and disturbed. The feeding stations in the backyards were deserted. The 
few birds seen anywhere were moribund; they trembled violently and could not fly. It was a 
spring without voices. On the mornings that had once throbbed with the dawn chorus of robins, 
catbirds, doves, jays, wrens, and scores of other bird voices there was now no sound; only 
silence lay over the fields and woods and marsh. 

On the farms the hens brooded, but no chicks hatched. The farmers complained that they were 
unable to raise any pigs— the litters were small and the young survived only a few days. The 
apple trees were coming into bloom but no bees droned among the blossoms, so there was no 
pollination and there would be no fruit. The roadsides, once so attractive, were now lined with 
browned and withered vegetation as though swept by fire. These, too, were silent, deserted by 
all living things. Even the streams were now lifeless. Anglers no longer visited them, for all the 
fish had died. 

In the gutters under the eaves and between the shingles of the roofs, a white granular powder 
still showed a few patches; some weeks before it had fallen like snow upon the roofs and the 
lawns, the fields and streams. No witchcraft, no enemy action had silenced the rebirth of new 
life in this stricken world. The people had done it themselves. 

. . .This town does not actually exist, but it might easily have a thousand counterpa rts in 
America or elsewhere in the world. I know of no community that has experienced all the 

misfortunes I describe. Yet everyone of these disasters has actually happened somewhere, and 
many real communities have already suffered a substantial number of them. A grim specter 
has crept upon us almost unnoticed, and this imagined tragedy may easily become a stark 
reality we all shall know. What has already silenced the voices of spring in countless towns in 
America? This book is an attempt to explain. 

2. The Obligation to Endure 

THE HISTORY OF LIFE on earth has been a history of interaction between living things 
and their surroundings. To a large extent, the physical form and the habits of the earth's 
vegetation and its animal life have been molded by the environment. Considering the whole 
span of earthly time, the opposite effect, in which life actually modifies its surroundings, has 
been relatively slight. Only within the moment of time represented by the present century has 
one species— man— acquired significant power to alter the nature of his world. 
During the past quarter century this power has not only increased to one of disturbing 
magnitude but it has changed in character. The most alarming of all man's assaults upon the 
environment is the contamination of air, earth, rivers, and sea with dangerous and even lethal 
materials. This pollution is for the most part irrecoverable; the chain of evil it initiates not 
only in the world that must support life but in living tissues is for the most part irreversible. In 
this now universal contamination of the environment, chemicals are the sinister and little- 
recognized partners of radiation in changing the very nature of the world— the very nature of 
its life. Strontium 90, released through nuclear explosions into the air, comes to earth in rain or 
drifts down as fallout, lodges in soil, enters into the grass or corn or wheat grown there, and in 
time takes up its abode in the bones of a human being, there to remain until his death. 
Similarly, chemicals sprayed on croplands or forests or gardens lie long in soil, entering into 
living organisms, passing from one to another in a chain of poisoning and death. Or they pass 
mysteriously by underground streams until they emerge and, through the alchemy of air and 
sunlight, combine into new forms that kill vegetation, sicken cattle, and work unknown harm on 
those who drink from once pure wells. As Albert Schweitzer has said, 'Man can hardly even 
recognize the devils of his own creation.' It took hundreds of millions of years to produce the 
life that now inhabits the earth— eons of time in which that developing and evolving and 
diversifying life reached a state of adjustment and balance with its surroundings. The 
environment, rigorously shaping and directing the life it supported, contained elements that 
were hostile as well as supporting. Certain rocks gave out dangerous radiation; even within the 
light of the sun, from which all life draws its energy, there were short-wave radiations with 
power to injure. Given time— time not in years but in millennia— life adjusts, and a balance has 
been reached. For time is the essential ingredient; but in the modern world there is no time. 
The rapidity of change and the speed with which new situations are created follow the 
impetuous and heedless pace of man rather than the deliberate pace of nature. Radiation is no 
longer merely the background radiation of rocks, the bombardment of cosmic rays, the 
ultraviolet of the sun that have existed before there was any life on earth; radiation is now the 
unnatural creation of man's tampering with the atom. The chemicals to which life is asked to 
make its adjustment are no longer merely the calcium and silica and copper and all the rest of 
the minerals washed out of the rocks and carried in rivers to the sea; they are the synthetic 
creations of man's inventive mind, brewed in his laboratories, and having no counterparts in 

To adjust to these chemicals would require time on the scale that is nature's; it would require 
not merely the years of a man's life but the life of generations. And even this, were it by some 
miracle possible, would be futile, for the new chemicals come from our laboratories in an 

endless stream; almost five hundred annually find their way into actual use in the United States 
alone. The figure is staggering and its implications are not easily grasped— 500 new chemicals 
to which the bodies of men and animals are required somehow to adapt each year, chemicals 
totally outside the limits of biologic experience. 

Among them are many that are used in man's war against nature. Since the mid-1940s over 200 
basic chemicals have been created for use in killing insects, weeds, rodents, and other 
organisms described in the modern vernacular as 'pests'; and they are sold under several 
thousand different brand names. These sprays, dusts, and aerosols are now applied almost 
universally to farms, gardens, forests, and homes— nonselective chemicals that have the power 
to kill every insect, the 'good' and the 'bad', to still the song of birds and the leaping of fish in 
the streams, to coat the leaves with a deadly film, and to linger on in soil— all this though the 
intended target may be only a few weeds or insects. Can anyone believe it is possible to lay 
down such a barrage of poisons on the surface of the earth without making it unfit for all life? 
They should not be called 'insecticides', but 'biocides'. The whole process of spraying seems 
caught up in an endless spiral. Since DDT was released for civilian use, a process of escalation 
has been going on in which ever more toxic materials must be found. This has happened 
because insects, in a triumphant vindication of Darwin's principle of the survival of the fittest, 
have evolved super races immune to the particular insecticide used, hence a deadlier one has 
always to be developed— and then a deadlier one than that. It has happened also because, for 
reasons to be described later, destructive insects often undergo a 'flareback', or resurgence, 
after spraying, in numbers greater than before. Thus the chemical war is never won, and all life 
is caught in its violent crossfire. 

Along with the possibility of the extinction of mankind by nuclear war, the central problem of 
our age has therefore become the contamination of man's total environment with such 
substances of incredible potential for harm— substances that accumulate in the tissues of 
plants and animals and even penetrate the germ cells to shatter or alter the very material 
of heredity upon which the shape of the future depends. 

Some would-be architects of our future look toward a time when it will be possible to alter the 
human germ plasm by design. But we may easily be doing so now by inadvertence, for many 
chemicals, like radiation, bring about gene mutations. It is ironic to think that man might 
determine his own future by something so seemingly trivial as the choice of an insect spray. 
All this has been risked— for what? Future historians may well be amazed by our distorted 
sense of proportion. How could intelligent beings seek to control a few unwanted species by a 
method that contaminated the entire environment and brought the threat of disease and death 
even to their own kind? Yet this is precisely what we have done. We have done it, moreover, 
for reasons that collapse the moment we examine them. We are told that the enormous and 
expanding use of pesticides is necessary to maintain farm production. Yet is our real problem 
not one of overproduction? Our farms, despite measures to remove acreages from production 
and to pay farmers not to produce, have yielded such a staggering excess of crops that the 
American taxpayer in 1962 is paying out more than one billion dollars a year as the total 
carrying cost of the surplus-food storage program. And is the situation helped when one branch 
of the Agriculture Department tries to reduce production while another states, as it did in 1958, 
'It is believed generally that reduction of crop acreages under provisions of the Soil Bank will 
stimulate interest in use of chemicals to obtain maximum production on the land retained in 

crops.' All this is not to say there is no insect problem and no need of control. I am saying, 
rather, that control must be geared to realities, not to mythical situations, and that the 
methods employed must be such that they do not destroy us along with the insects. 
. . . The problem whose attempted solution has brought such a train of disaster in its wake is an 
accompaniment of our modern way of life. Long before the age of man, insects inhabited the 
earth— a group of extraordinarily varied and adaptable beings. Over the course of time since 
man's advent, a small percentage of the more than half a million species of insects have come 
into conflict with human welfare in two principal ways: as competitors for the food supply and 
as carriers of human disease. Disease-carrying insects become important where human beings 
are crowded together, especially under conditions where sanitation is poor, as in time of 
natural disaster or war or in situations of extreme poverty and deprivation. Then control of 
some sort becomes necessary. It is a sobering fact, however, as we shall presently see, that the 
method of massive chemical control has had only limited success, and also threatens to worsen 
the very conditions it is intended to curb. 

Under primitive agricultural conditions the farmer had few insect problems. These arose with 
the intensification of agriculture— the devotion of immense acreages to a single crop. Such a 
system set the stage for explosive increases in specific insect populations. Single-crop farming 
does not take advantage of the principles by which nature works; it is agriculture as an engineer 
might conceive it to be. Nature has introduced great variety into the landscape, but man has 
displayed a passion for simplifying it. Thus he undoes the built-in checks and balances by which 
nature holds the species within bounds. One important natural check is a limit on the amount 
of suitable habitat for each species. Obviously then, an insect that lives on wheat can build up 
its population to much higher levels on a farm devoted to wheat than on one in which wheat is 
intermingled with other crops to which the insect is not adapted. The same thing happens in 
other situations. A generation or more ago, the towns of large areas of the United States lined 
their streets with the noble elm tree. Now the beauty they hopefully created is threatened with 
complete destruction as disease sweeps through the elms, carried by a beetle that would have 
only limited chance to build up large populations and to spread from tree to tree if the elms 
were only occasional trees in a richly diversified planting. 

Another factor in the modern insect problem is one that must be viewed against a background 
of geologic and human history: the spreading of thousands of different kinds of organisms from 
their native homes to invade new territories. This worldwide migration has been studied and 
graphically described by the British ecologist Charles Elton in his recent book The Ecology of 
Invasions. During the Cretaceous Period, some hundred million years ago, flooding seas cut 
many land bridges between continents and living things found themselves confined in what 
Elton calls 'colossal separate nature reserves'. There, isolated from others of their kind, they 
developed many new species. When some of the land masses were joined again, about 15 
million years ago, these species began to move out into new territories— a movement that is 
not only still in progress but is now receiving considerable assistance from man. 
The importation of plants is the primary agent in the modern spread of species, for animals 
have almost invariably gone along with the plants, quarantine being a comparatively recent and 
not completely effective innovation. The United States Office of Plant Introduction alone has 
introduced almost 200,000 species and varieties of plants from all over the world. Nearly half of 
the 180 or so major insect enemies of plants in the United States are accidental imports from 

abroad, and most of them have come as hitchhikers on plants. In new territory, out of reach of 
the restraining hand of the natural enemies that kept down its numbers in its native land, an 
invading plant or animal is able to become enormously abundant. Thus it is no accident that our 
most troublesome insects are introduced species. These invasions, both the naturally occurring 
and those dependent on human assistance, are likely to continue indefinitely. Quarantine and 
massive chemical campaigns are only extremely expensive ways of buying time. We are faced, 
according to Dr. Elton, 'with a life-and-death need not just to find new technological means of 
suppressing this plant or that animal'; instead we need the basic knowledge of animal 
populations and their relations to their surroundings that will 'promote an even balance and 
damp down the explosive power of outbreaks and new invasions.' 

Much of the necessary knowledge is now available but we do not use it. We train ecologists in 
our universities and even employ them in our governmental agencies but we seldom take their 
advice. We allow the chemical death rain to fall as though there were no alternative, whereas 
in fact there are many, and our ingenuity could soon discover many more if given opportunity. 
Have we fallen into a mesmerized state that makes us accept as inevitable that which is inferior 
or detrimental, as though having lost the will or the vision to demand that which is good? Such 
thinking, in the words of the ecologist Paul Shepard, 'idealizes life with only its head out of 
water, inches above the limits of toleration of the corruption of its own environment. ..Why 
should we tolerate a diet of weak poisons, a home in insipid surroundings, a circle of 
acquaintances who are not quite our enemies, the noise of motors with just enough relief to 
prevent insanity? Who would want to live in a world which is just not quite fatal?' 
Yet such a world is pressed upon us. The crusade to create a chemically sterile, insect-free 
world seems to have engendered a fanatic zeal on the part of many specialists and most of the 
so-called control agencies. On every hand there is evidence that those engaged in spraying 
operations exercise a ruthless power. 'The regulatory entomologists. ..function as prosecutor, 
judge and jury, tax assessor and collector and sheriff to enforce their own orders,' said 
Connecticut entomologist Neely Turner. The most flagrant abuses go unchecked in both state 
and federal agencies. It is not my contention that chemical insecticides must never be used. I do 
contend that we have put poisonous and biologically potent chemicals indiscriminately into the 
hands of persons largely or wholly ignorant of their potentials for harm. We have subjected 
enormous numbers of people to contact with these poisons, without their consent and often 
without their knowledge. If the Bill of Rights contains no guarantee that a citizen shall be secure 
against lethal poisons distributed either by private individuals or by public officials, it is surely 
only because our forefathers, despite their considerable wisdom and foresight, could conceive 
of no such problem. 

I contend, furthermore, that we have allowed these chemicals to be used with little or no 
advance investigation of their effect on soil, water, wildlife, and man himself. Future 
generations are unlikely to condone our lack of prudent concern for the integrity of the natural 
world that supports all life. There is still very limited awareness of the nature of the threat. This 
is an era of specialists, each of whom sees his own problem and is unaware of or intolerant of 
the larger frame into which it fits. It is also an era dominated by industry, in which the right to 
make a dollar at whatever cost is seldom challenged. When the public protests, confronted with 
some obvious evidence of damaging results of pesticide applications, it is fed little tranquilizing 
pills of half truth. We urgently need an end to these false assurances, to the sugar coating of 

unpalatable facts. It is the public that is being asked to assume the risks that the insect 
controllers calculate. The public must decide whether it wishes to continue on the present 
road, and it can do so only when in full possession of the facts. In the words of Jean Rostand, 
'The obligation to endure gives us the right to know.' 

3. Elixirs of Death 

FOR THE FIRST TIME in the history of the world, every human being is now subjected to 
contact with dangerous chemicals, from the moment of conception until death. In the less than 
two decades of their use, the synthetic pesticides have been so thoroughly distributed 
throughout the animate and inanimate world that they occur virtually everywhere. They have 
been recovered from most of the major river systems and even from streams of groundwater 
flowing unseen through the earth. Residues of these chemicals linger in soil to which they may 
have been applied a dozen years before. They have entered and lodged in the bodies offish, 
birds, reptiles, and domestic and wild animals so universally that scientists carrying on animal 
experiments find it almost impossible to locate subjects free from such contamination. They 
have been found in fish in remote mountain lakes, in earthworms burrowing in soil, in the eggs 
of birds— and in man himself. For these chemicals are now stored in the bodies of the vast 
majority of human beings, regardless of age. They occur in the mother's milk, and probably in 
the tissues of the unborn child. All this has come about because of the sudden rise and 
prodigious growth of an industry for the production of manmade or synthetic chemicals with 
insecticidal properties. This industry is a child of the Second World War. In the course of 
developing agents of chemical warfare, some of the chemicals created in the laboratory were 
found to be lethal to insects. The discovery did not come by chance: insects were widely used 
to test chemicals as agents of death for man. The result has been a seemingly endless stream of 
synthetic insecticides. In being man-made— by ingenious laboratory manipulation of the 
molecules, substituting atoms, altering their arrangement— they differ sharply from the simpler 
insecticides of prewar days. These were derived from naturally occurring minerals and plant 
products— compounds of arsenic, copper, , manganese, zinc, and other minerals, pyrethrum 
from the dried flowers of chrysanthemums, nicotine sulphate from some of the relatives of 
tobacco, and rotenone from leguminous plants of the East Indies. 

What sets the new synthetic insecticides apart is their enormous biological potency. They have 
immense power not merely to poison but to enter into the most vital processes of the body and 
change them in sinister and often deadly ways. Thus, as we shall see, they destroy the very 
enzymes whose function is to protect the body from harm, they block the oxidation processes 
from which the body receives its energy, they prevent the normal functioning of various organs, 
and they may initiate in certain cells the slow and irreversible change that leads to malignancy. 
Yet new and more deadly chemicals are added to the list each year and new uses are devised so 
that contact with these materials has become practically worldwide. The production of 
synthetic pesticides in the United States soared from 124,259,000 pounds in 1947 to 
637,666,000 pounds in 1960— more than a fivefold increase. The wholesale value of these 
products was well over a quarter of a billion dollars. But in the plans and hopes of the industry 
this enormous production is only a beginning. 

A Who's Who of pesticides is therefore of concern to us all. If we are going to live so intimately 
with these chemicals— eating and drinking them, taking them into the very marrow of our 
bones— we had better know something about their nature and their power. Although the 
Second World War marked a turning away from inorganic chemicals as pesticides into the 
wonder world of the carbon molecule, a few of the old materials persist. Chief among these is 

arsenic, which is still the basic ingredient in a variety of weed and insect killers. Arsenic is a 
highly toxic mineral occurring widely in association with the ores of various metals, and in very 
small amounts in volcanoes, in the sea, and in spring water. Its relations to man are varied and 
historic. Since many of its compounds are tasteless, it has been a favorite agent of homicide 
from long before the time of the Borgias to the present. Arsenic is present in English chimney 
soot and along with certain aromatic hydrocarbons is considered responsible for the 
carcinogenic (or cancer-causing) action of the soot, which was recognized nearly two centuries 
ago by an English physician. Epidemics of chronic arsenical poisoning involving whole 
populations over long periods are on record. Arsenic-contaminated environments have also 
caused sickness and death among horses, cows, goats, pigs, deer, fishes, and bees; despite this 
record arsenical sprays and dusts are widely used. In the arsenic-sprayed cotton country of 
southern United States beekeeping as an industry has nearly died out. Farmers using arsenic 
dusts over long periods have been afflicted with chronic arsenic poisoning, livestock have been 
poisoned by crop sprays or weed killers containing arsenic. Drifting arsenic dusts from 
blueberry lands have spread over neighboring farms, contaminating streams, fatally poisoning 
bees and cows, and causing human illness. 'It is scarcely possible. handle arsenicals with 
more utter disregard of the general health than that which has been practiced in our country in 
recent years,' said Dr. W. C. Hueper, of the National Cancer Institute, an authority on 
environmental cancer. 'Anyone who has watched the dusters and sprayers of arsenical 
insecticides at work must have been impressed by the almost supreme carelessness with which 
the poisonous substances are dispensed.' . . . 

Modern insecticides are still more deadly. The vast majority fall into one of two large groups of 
chemicals. One, represented by DDT, is known as the 'chlorinated hydrocarbons. The other 
group consists of the organic phosphorus insecticides, and is represented by the reasonably 
familiar malathion and parathion. All have one thing in common. As mentioned above, they are 
built on a basis of carbon atoms, which are also the indispensable building blocks of the living 
world, and thus classed as 'organic'. To understand them, we must see of what they are made, 
and how, although linked with the basic chemistry of all life, they lend themselves to the 
modifications which make them agents of death. 

The basic element, carbon, is one whose atoms have an almost infinite capacity for uniting with 
each other in chains and rings and various other configurations, and for becoming linked with 
atoms of other substances. Indeed, the incredible diversity of living creatures from bacteria to 
the great blue whale is largely due to this capacity of carbon. The complex protein molecule has 
the carbon atom as its basis, as have molecules of fat, carbohydrates, enzymes, and vitamins. 
So, too, have enormous numbers of nonliving things, for carbon is not necessarily a symbol of 
life. Some organic compounds are simply combinations of carbon and hydrogen. The simplest 
of these is methane, or marsh gas, formed in nature by the bacterial decomposition of organic 
matter underwater. Mixed with air in proper proportions, methane becomes the dreaded 'fire 
damp' of coal mines. Its structure is beautifully simple, consisting of one carbon atom to which 

four hydrogen atoms have become attached: 




Chemists have discovered that it is possible to detach one or all of the hydrogen atoms and 
substitute other elements. For example, by substituting one atom of chlorine for one of 
hydrogen we produce methyl chloride: 

Take away three hydrogen atoms and substitute chlorine and we have the anesthetic 


Substitute chlorine atoms for all of the hydrogen atoms and the result is carbon tetrachloride, 
the familiar cleaning fluid: 


In the simplest possible terms, these changes rung upon the basic molecule of methane 
illustrate what a chlorinated hydrocarbon is. But this illustration gives little hint of the true 
complexity of the chemical world of the hydrocarbons, or of the manipulations by which the 
organic chemist creates his infinitely varied materials. For instead of the simple methane 
molecule with its single carbon atom, he may work with hydrocarbon molecules consisting of 
many carbon atoms, arranged in rings or chains, with side chains or branches, holding to 
themselves with chemical bonds not merely simple atoms of hydrogen or chlorine but also a 
wide variety of chemical groups. By seemingly slight changes the whole character of the 
substance is changed; for example, not only what is attached but the place of attachment to 

the carbon atom is highly important. Such ingenious manipulations have produced a battery of 
poisons of truly extraordinary power. . . . 

DDT (short for dichloro-diphenyl-trichloro-ethane) was first synthesized by a German chemist in 
1874, but its properties as an insecticide were not discovered until 1939. Almost immediately 
DDT was hailed as a means of stamping out insect-borne disease and winning the farmers' war 
against crop destroyers overnight. The discoverer, Paul Muller of Switzerland, won the Nobel 
Prize. DDT is now so universally used that in most minds the product takes on the harmless 
aspect of the familiar. Perhaps the myth of the harmlessness of DDT rests on the fact that one 
of its first uses was the wartime dusting of many thousands of soldiers, refugees, and prisoners, 
to combat lice. It is widely believed that since so many people came into extremely intimate 
contact with DDT and suffered no immediate ill effects the chemical must certainly be innocent 
of harm. This understandable misconception arises from the fact that— unlike other chlorinated 
hydrocarbons— DDT in powder form is not readily absorbed through the skin. Dissolved in oil, as 
it usually is, DDT is definitely toxic. If swallowed, it is absorbed slowly through the digestive 
tract; it may also be absorbed through the lungs. Once it has entered the body it is stored 
largely in organs rich in fatty substances (because DDT itself is fat-soluble) such as the adrenals, 
testes, or thyroid. Relatively large amounts are deposited in the liver, kidneys, and the fat of the 
large, protective mesenteries that enfold the intestines. 

This storage of DDT begins with the smallest conceivable intake of the chemical (which is 
present as residues on most foodstuffs) and continues until quite high levels are reached. The 
fatty storage depots act as biological magnifiers, so that an intake of as little as of 1 part per 
million in the diet results in storage of about 10 to 15 parts per million, an increase of one 
hundredfold or more. These terms of reference, so commonplace to the chemist or the 
pharmacologist, are unfamiliar to most of us. One part in a million sounds like a very small 
amount— and so it is. But such substances are so potent that a minute quantity can bring about 
vast changes in the body. In animal experiments, 3 parts per million has been found to inhibit 
an essential enzyme in heart muscle; only 5 parts per million has brought about necrosis or 
disintegration of liver cells; only 2.5 parts per million of the closely related chemicals dieldrin 
and chlordane did the same. This is really not surprising. In the normal chemistry of the human 
body there is just such a disparity between cause and effect. For example, a quantity of iodine 
as small as two ten-thousandths of a gram spells the difference between health and disease. 
Because these small amounts of pesticides are cumulatively stored and only slowly excreted, 
the threat of chronic poisoning and degenerative changes of the liver and other organs is very 

Scientists do not agree upon how much DDT can be stored in the human body. Dr. Arnold 
Lehman, who is the chief pharmacologist of the Food and Drug Administration, says there is 
neither a floor below which DDT is not absorbed nor a ceiling beyond which absorption and 
storage ceases. On the other hand, Dr. Wayland Hayes of the United States Public Health 
Service contends that in every individual a point of equilibrium is reached, and that DDT in 
excess of this amount is excreted. For practical purposes it is not particularly important which 
of these men is right. Storage in human beings has been well investigated, and we know that 
the average person is storing potentially harmful amounts. According to various studies, 
individuals with no known exposure (except the inevitable dietary one) store an average of 5.3 
parts per million to 7.4 parts per million; agricultural workers 17.1 parts per million; and 

workers in insecticide plants as high as 648 parts per million! So the range of proven storage is 
quite wide and, what is even more to the point, the minimum figures are above the level at 
which damage to the liver and other organs or tissues may begin. One of the most sinister 
features of DDT and related chemicals is the way they are passed on from one organism to 
another through all the links of the food chains. For example, fields of alfalfa are dusted with 
DDT; meal is later prepared from the alfalfa and fed to hens; the hens lay eggs which contain 
DDT. Or the hay, containing residues of 7 to 8 parts per million, may be fed to cows. The DDT 
will turn up in the milk in the amount of about 3 parts per million, but in butter made from this 
milk the concentration may run to 65 parts per million. Through such a process of transfer, 
what started out as a very small amount of DDT may end as a heavy concentration. Farmers 
nowadays find it difficult to obtain uncontaminated fodder for their milk cows, though the Food 
and Drug Administration forbids the presence of insecticide residues in milk shipped in 
interstate commerce. 

The poison may also be passed on from mother to offspring. Insecticide residues have been 
recovered from human milk in samples tested by Food and Drug Administration scientists. This 
means that the breast-fed human infant is receiving small but regular additions to the load of 
toxic chemicals building up in his body. It is by no means his first exposure, however: there is 
good reason to believe this begins while he is still in the womb. In experimental animals the 
chlorinated hydrocarbon insecticides freely cross the barrier of the placenta, the traditional 
protective shield between the embryo and harmful substances in the mother's body. While the 
quantities so received by human infants would normally be small, they are not unimportant 
because children are more susceptible to poisoning than adults. This situation also means that 
today the average individual almost certainly starts life with the first deposit of the growing 
load of chemicals his body will be required to carry thenceforth. 

All these facts— storage at even low levels, subsequent accumulation, and occurrence of liver 
damage at levels that may easily occur in normal diets, caused Food and Drug Administration 
scientists to declare as early as 1950 that it is 'extremely likely the potential hazard of DDT has 
been underestimated.' There has been no such parallel situation in medical history. No one yet 
knows what the ultimate consequences may be. . . . 

Chlordane, another chlorinated hydrocarbon, has all these unpleasant attributes of DDT plus a 
few that are peculiarly its own. Its residues are long persistent in soil, on foodstuffs, or on 
surfaces to which it may be applied. Chlordane makes use of all available portals to enter the 
body. It may be absorbed through the skin, may be breathed in as a spray or dust, and of course 
is absorbed from the digestive tract if residues are swallowed. Like all other chlorinated 
hydrocarbons, its deposits build up in the body in cumulative fashion. A diet containing such a 
small amount of chlordane as 2.5 parts per million may eventually lead to storage of 75 parts 
per million in the fat of experimental animals. So experienced a pharmacologist as Dr. Lehman 
has described chlordane in 1950 as 'one of the most toxic of insecticides— anyone handling it 
could be poisoned.' Judging by the carefree liberality with which dusts for lawn treatments by 
suburbanites are laced with chlordane, this warning has not been taken to heart. The fact that 
the suburbanite is not instantly stricken has little meaning, for the toxins may sleep long in his 
body, to become manifest months or years later in an obscure disorder almost impossible to 
trace to its origins. On the other hand, death may strike quickly. One victim who accidentally 
spilled a 25 per cent industrial solution on the skin developed symptoms of poisoning within 40 

minutes and died before medical help could be obtained. No reliance can be placed on 
receiving advance warning which might allow treatment to be had in time. 
Heptachlor, one of the constituents of chlordane, is marketed as a separate formulation. It has 
a particularly high capacity for storage in fat. If the diet contains as little as of 1 part per million 
there will be measurable amounts of heptachlor in the body. It also has the curious ability to 
undergo change into a chemically distinct substance known as heptachlor epoxide. It does this 
in soil and in the tissues of both plants and animals. Tests on birds indicate that the epoxide 
that results from this change is more toxic than the original chemical, which in turn is four times 
as toxic as chlordane. As long ago as the mid-1930s a special group of hydrocarbons, the 
chlorinated naphthalenes, was found to cause hepatitis, and also a rare and almost invariably 
fatal liver disease in persons subjected to occupational exposure. They have led to illness and 
death of workers in electrical industries; and more recently, in agriculture, they have been 
considered a cause of a mysterious and usually fatal disease of cattle. In view of these 
antecedents, it is not surprising that three of the insecticides that are related to this group are 
among the most violently poisonous of all the hydrocarbons. These are dieldrin, aldrin, and 
endrin. Dieldrin, named for a German chemist, Diels, is about 5 times as toxic as DDT when 
swallowed but 40 times as toxic when absorbed through the skin in solution. It is notorious for 
striking quickly and with terrible effect at the nervous system, sending the victims into 
convulsions. Persons thus poisoned recover so slowly as to indicate chronic effects. As with 
other chlorinated hydrocarbons, these long-term effects include severe damage to the liver. 
The long duration of its residues and the effective insecticidal action make dieldrin one of the 
most used insecticides today, despite the appalling destruction of wildlife that has followed its 
use. As tested on quail and pheasants, it has proved to be about 40 to 50 times as toxic as DDT. 
There are vast gaps in our knowledge of how dieldrin is stored or distributed in the body, or 
excreted, for the chemists' ingenuity in devising insecticides has long ago outrun biological 
knowledge of the way these poisons affect the living organism. However, there is every 
indication of long storage in the human body, where deposits may lie dormant like a slumbering 
volcano, only to flare up in periods of physiological stress when the body draws upon its fat 
reserves. Much of what we do know has been learned through hard experience in the 
antimalarial campaigns carried out by the World Health Organization. As soon as dieldrin was 
substituted for DDT in ma I aria -control work (because the malaria mosquitoes had become 
resistant to DDT), cases of poisoning among the spraymen began to occur. The seizures were 
severe— from half to all (varying in the different programs) of the men affected went into 
convulsions and several died. Some had convulsions as long as four months after the last 

Aldrin is a somewhat mysterious substance, for although it exists as a separate entity it bears 
the relation of alter ego to dieldrin. When carrots are taken from a bed treated with aldrin they 
are found to contain residues of dieldrin. This change occurs in living tissues and also in soil. 
Such alchemistic transformations have led to many erroneous reports, for if a chemist, knowing 
aldrin has been applied, tests for it he will be deceived into thinking all residues have been 
dissipated. The residues are there, but they are dieldrin and this requires a different test. Like 
dieldrin, aldrin is extremely toxic. It produces degenerative changes in the liver and kidneys. A 
quantity the size of an aspirin tablet is enough to kill more than 400 quail. Many cases of human 
poisonings are on record, most of them in connection with industrial handling. Aldrin, like most 

of this group of insecticides, projects a menacing shadow into the future, the shadow of 
sterility. Pheasants fed quantities too small to kill them nevertheless laid few eggs, and the 
chicks that hatched soon died. The effect is not confined to birds. Rats exposed to aldrin had 
fewer pregnancies and their young were sickly and short-lived. Puppies born of treated mothers 
died within three days. By one means or another, the new generations suffer for the poisoning 
of their parents. No one knows whether the same effect will be seen in human beings, yet this 
chemical has been sprayed from airplanes over suburban areas and farmlands. 
Endrin is the most toxic of all the chlorinated hydrocarbons. Although chemically rather closely 
related to dieldrin, a little twist in its molecular structure makes it 5 times as poisonous. It 
makes the progenitor of all this group of insecticides, DDT, seem by comparison almost 
harmless. It is 15 times as poisonous as DDT to mammals, 30 times as poisonous to fish, and 
about 300 times as poisonous to some birds. In the decade of its use, endrin has killed 
enormous numbers of fish, has fatally poisoned cattle that have wandered into sprayed 
orchards, has poisoned wells, and has drawn a sharp warning from at least one state health 
department that its careless use is endangering human lives. In one of the most tragic cases of 
endrin poisoning there was no apparent carelessness; efforts had been made to take 
precautions apparently considered adequate. A year-old child had been taken by his American 
parents to live in Venezuela. There were cockroaches in the house to which they moved, and 
after a few days a spray containing endrin was used. The baby and the small family dog were 
taken out of the house before the spraying was done about nine o'clock one morning. After the 
spraying the floors were washed. The baby and dog were returned to the house in 
midafternoon. An hour or so later the dog vomited, went into convulsions, and died. At 10 p.m. 
on the evening of the same day the baby also vomited, went into convulsions, and lost 
consciousness. After that fateful contact with endrin this normal, healthy child became little 
more than a vegetable— unable to see or hear, subject to frequent muscular spasms, 
apparently completely cut off from contact with his surroundings. Several months of treatment 
in a New York hospital failed to change his condition or bring hope of change. 'It is extremely 
doubtful,' reported the attending physicians, 'that any useful degree of recovery will occur.' . . . 
The second major group of insecticides, the alkyl or organic phosphates, are among the most 
poisonous chemicals in the world. The chief and most obvious hazard attending their use is that 
of acute poisoning of people applying the sprays or accidentally coming in contact with drifting 
spray, with vegetation coated by it, or with a discarded container. In Florida, two children found 
an empty bag and used it to repair a swing. Shortly thereafter both of them died and three of 
their playmates became ill. The bag had once contained an insecticide called parathion, one of 
the organic phosphates; tests established death by parathion poisoning. On another occasion 
two small boys in Wisconsin, cousins, died on the same night. One had been playing in his yard 
when spray drifted in from an adjoining field where his father was spraying potatoes with 
parathion; the other had run playfully into the barn after his father and had put his hand on the 
nozzle of the spray equipment. 

The origin of these insecticides has a certain ironic significance. Although some of the chemicals 
themselves— organic esters of phosphoric acid— had been known for many years, their 
insecticidal properties remained to be discovered by a German chemist, Gerhard Schrader, in 
the late 1930s. Almost immediately the German government recognized the value of these 
same chemicals as new and devastating weapons in man's war against his own kind, and the 

work on them was declared secret. Some became the deadly nerve gases. Others, of closely 
allied structure, became insecticides. The organic phosphorus insecticides act on the living 
organism in a peculiar way. They have the ability to destroy enzymes— enzymes that perform 
necessary functions in the body. Their target is the nervous system, whether the victim is an 
insect or a warm-blooded animal. Under normal conditions, an impulse passes from nerve to 
nerve with the aid of a 'chemical transmitter' called acetylcholine, a substance that performs an 
essential function and then disappears. Indeed, its existence is so ephemeral that medical 
researchers are unable, without special procedures, to sample it before the body has destroyed 
it. This transient nature of the transmitting chemical is necessary to the normal functioning of 
the body. If the acetylcholine is not destroyed as soon as a nerve impulse has passed, impulses 
continue to flash across the bridge from nerve to nerve, as the chemical exerts its effects in an 
ever more intensified manner. The movements of the whole body become uncoordinated: 
tremors, muscular spasms, convulsions, and death quickly result. This contingency has been 
provided for by the body. A protective enzyme called cholinesterase is at hand to destroy the 
transmitti ng chemical once it is no longer needed. By this means a precise balance is struck and 
the body never builds up a dangerous amount of acetylcholine. But on contact with the organic 
phosphorus insecticides, the protective enzyme is destroyed, and as the quantity of the enzyme 
is reduced that of the transmitting chemical builds up. In this effect, the organic phosphorus 
compounds resemble the alkaloid poison muscarine, found in a poisonous mushroom, the fly 

Repeated exposures may lower the cholinesterase level until an individual reaches the brink of 
acute poisoning, a brink over which he may be pushed by a very small additional exposure. For 
this reason it is considered important to make periodic examinations of the blood of spray 
operators and others regularly exposed. Parathion is one of the most widely used of the organic 
phosphates. It is also one of the most powerful and dangerous. Honeybees become 'wildly 
agitated and bellicose' on contact with it, perform frantic cleaning movements, and are near 
death within half an hour. A chemist, thinking to learn by the most direct possible means the 
dose acutely toxic to human beings, swallowed a minute amount, equivalent to about .00424 
ounce. Paralysis followed so instantaneously that he could not reach the antidotes he had 
prepared at hand, and so he died. Parathion is now said to be a favorite instrument of suicide in 
Finland. In recent years the State of California has reported an average of more than 200 cases 
of accidental parathion poisoning annually. In many parts of the world the fatality rate from 
parathion is startling: 100 fatal cases in India and 67 in Syria in 1958, and an average of 336 
deaths per year in Japan. Yet some 7,000,000 pounds of parathion are now applied to fields and 
orchards of the United States— by hand sprayers, motorized blowers and dusters, and by 
airplane. The amount used on California farms alone could, according to one medical authority, 
'provide a lethal dose for 5 to 10 times the whole world's population.' 

One of the few circumstances that save us from extinction by this means is the fact that 
parathion and other chemicals of this group are decomposed rather rapidly. Their residues on 
the crops to which they are applied are therefore relatively short-lived compared with the 
chlorinated hydrocarbons. However, they last long enough to create hazards and produce 
consequences that range from the merely serious to the fatal. In Riverside, California, eleven 
out of thirty men picking oranges became violently ill and all but one had to be hospitalized. 
Their symptoms were typical of parathion poisoning. 

The grove had been sprayed with parathion some two and a half weeks earlier; the residues 
that reduced them to retching, half-blind, semiconscious misery were sixteen to nineteen days 
old. And this is not by any means a record for persistence. Similar mishaps have occurred in 
groves sprayed a month earlier, and residues have been found in the peel of oranges six 
months after treatment with standard dosages. The danger to all workers applying the organic 
phosphorus insecticides in fields, orchards, and vineyards, is so extreme that some states using 
these chemicals have established laboratories where physicians may obtain aid in diagnosis and 
treatment. Even the physicians themselves may be in some danger, unless they wear rubber 
gloves in handling the victims of poisoning. So may a laundress washing the clothing of such 
victims, which may have absorbed enough parathion to affect her. 

Malathion, another of the organic phosphates, is almost as familiar to the public as DDT, being 
widely used by gardeners, in household insecticides, in mosquito spraying, and in such blanket 
attacks on insects as the spraying of nearly a million acres of Florida communities for the 
Mediterranean fruit fly. It is considered the least toxic of this group of chemicals and many 
people assume they may use it freely and without fear of harm. Commercial advertising 
encourages this comfortable attitude. The alleged 'safety' of malathion rests on rather 
precarious ground, although— as often happens— this was not discovered until the chemical 
had been in use for several years. Malathion is 'safe' only because the mammalian liver, an 
organ with extraordinary protective powers, renders it relatively harmless. The detoxification is 
accomplished by one of the enzymes of the liver. If, however, something destroys this enzyme 
or interferes with its action, the person exposed to malathion receives the full force of the 

Unfortunately for all of us, opportunities for this sort of thing to happen a re legion. A few years 
ago a team of Food and Drug Administration scientists discovered that when malathion and 
certain other organic phosphates are administered simultaneously a massive poisoning 
results— up to 50 times as severe as would be predicted on the basis of adding together the 
toxicities of the two. In other words, of the lethal dose of each compound may be fatal when 
the two are combined. This discovery led to the testing of other combinations. It is now known 
that many pairs of organic phosphate insecticides are highly dangerous, the toxicity being 
stepped up or 'potentiated' through the combined action. Potentiation seems to take place 
when one compound destroys the liver enzyme responsible for detoxifying the other. The two 
need not be given simultaneously. The hazard exists not only for the man who may spray this 
week with one insecticide and next week with another; it exists also for the consumer of 
sprayed products. The common salad bowl may easily present a combination of organic 
phosphate insecticides. Residues well within the legally permissible limits may interact. The full 
scope of the dangerous interaction of chemicals is as yet little known, but disturbing findings 
now come regularly from scientific laboratories. Among these is the discovery that the toxicity 
of an organic phosphate can be increased by a second agent that is not necessarily an 
insecticide. For example, one of the plasticizing agents may act even more strongly than 
another insecticide to make malathion more dangerous. Again, this is because it inhibits the 
liver enzyme that normally would 'draw the teeth' of the poisonous insecticide. 
What of other chemicals in the normal human environment? What, in particular, of drugs? A 
bare beginning has been made on this subject, but already it is known that some organic 
phosphates (parathion and malathion) increase the toxicity of some drugs used as muscle 

relaxants, and that several others (again including malathion) markedly increase the sleeping 
time of barbiturates. . . . 

In Greek mythology the sorceress Medea, enraged at being supplanted by a rival for the 
affections of her husband Jason, presented the new bride with a robe possessing magic 
properties. The wearer of the robe immediately suffered a violent death. This death-by- 
indirection now finds its counterpart in what are known as 'systemic insecticides'. These are 
chemicals with extraordinary properties which are used to convert plants or animals into a sort 
of Medea's robe by making them actually poisonous. This is done with the purpose of killing 
insects that may come in contact with them, especially by sucking their juices or blood. 
The world of systemic insecticides is a weird world, surpassing the imaginings of the brothers 
Grimm— perhaps most closely akin to the cartoon world of Charles Addams. It is a world where 
the enchanted forest of the fairy tales has become the poisonous forest in which an insect that 
chews a leaf or sucks the sap of a plant is doomed. It is a world where a flea bites a dog, and 
dies because the dog's blood has been made poisonous, where an insect may die from vapors 
emanating from a plant it has never touched, where a bee may carry poisonous nectar back to 
its hive and presently produce poisonous honey. 

The entomologists' dream of the built-in insecticide was born when workers in the field of 
applied entomology realized they could take a hint from nature: they found that wheat growing 
in soil containing sodium selenate was immune to attack by aphids or spider mites. Selenium, a 
naturally occurring element found sparingly in rocks and soils of many parts of the world, thus 
became the first systemic insecticide. What makes an insecticide a systemic is the ability to 
permeate all the tissues of a plant or animal and make them toxic. This quality is possessed by 
some chemicals of the chlorinated hydrocarbon group and by others of the organophosphorus 
group, all synthetically produced, as well as by certain naturally occurring substances. In 
practice, however, most systemics are drawn from the organophosphorus group because the 
problem of residues is somewhat less acute. Systemics act in other devious ways. Applied to 
seeds, either by soaking or in a coating combined with carbon, they extend their effects into the 
following plant generation and produce seedlings poisonous to aphids and other sucking 
insects. Vegetables such as peas, beans, and sugar beets are sometimes thus protected. Cotton 
seeds coated with a systemic insecticide have been in use for some time in California, where 25 
farm labourers planting cotton in the San Joaquin Valley in 1959 were seized with sudden 
illness, caused by handling the bags of treated seeds. In England someone wondered what 
happened when bees made use of nectar from plants treated with systemics. This was 
investigated in areas treated with a chemical called schradan. Although the plants had been 
sprayed before the flowers were formed, the nectar later produced contained the poison. The 
result, as might have been predicted, was that the honey made by the bees also was 
contami nated with schradan. 

Use of animal systemics has concentrated chiefly on control of the cattle grub, a damaging 
parasite of livestock. Extreme care must be used in order to create an insecticidal effect in the 
blood and tissues of the host without setting up a fatal poisoning. The balance is delicate and 
government veterinarians have found that repeated small doses can gradually deplete an 
animal's supply of the protective enzyme cholinesterase, so that without warning a minute 
additional dose will cause poisoning. 

There are strong indications that fields closer to our daily lives are being opened up. You may 
now give your dog a pill which, it is claimed, will rid him of fleas by making his blood poisonous 
to them. The hazards discovered in treating cattle would presumably apply to the dog. As yet 
no one seems to have proposed a human systemic that would make us lethal to a mosquito. 
Perhaps this is the next step. . . . 

So far in this chapter we have been discussing the deadly chemicals that are being used in our 
war against the insects. What of our simultaneous war against the weeds? The desire for a 
quick and easy method of killing unwanted plants has given rise to a large and growing array of 
chemicals that are known as herbicides, or, less formally, as weed killers. The story of how 
these chemicals are used and misused will be told in Chapter 6; the question that here concerns 
us is whether the weed killers are poisons and whether their rise is contributing to the 
poisoning of the environment. 

The legend that the herbicides are toxic only to plants and so pose no threat to animal life has 
been widely disseminated, but unfortunately it is not true. The plant killers include a large 
variety of chemicals that act on animal tissue as well as on vegetation. They vary greatly in their 
action on the organism. Some are general poisons, some are powerful stimulants of 
metabolism, causing a fatal rise in body temperature, some induce malignant tumors either 
alone or in partnership with other chemicals, some strike at the genetic material of the race by 
causing gene mutations. The herbicides, then, like the insecticides, include some very 
dangerous chemicals, and their careless use in the belief that they are 'safe' can have disastrous 
results. Despite the competition of a constant stream of new chemicals issuing from the 
laboratories, arsenic compounds are still liberally used, both as insecticides (as mentioned 
above) and as weed killers, where they usually take the chemical form of sodium arsenite. The 
history of their use is not reassuring. As roadside sprays, they have cost many a farmer his cow 
and killed uncounted numbers of wild creatures. As aquatic weed killers in lakes and reservoirs 
they have made public waters unsuitable for drinking or even for swimming. As a spray applied 
to potato fields to destroy the vines they have taken a toll of human and nonhuman life. 
In England this latter practice developed about 1951 as a result of a shortage of sulfuric acid, 
formerly used to burn off the potato vines. The Ministry of Agriculture considered it necessary 
to give warning of the hazard of going into the arsenic-sprayed fields, but the warning was not 
understood by the cattle (nor, we must presume, by the wild animals and birds) and reports of 
cattle poisoned by the arsenic sprays came with monotonous regularity. When death came also 
to a farmer's wife through arsenic-contaminated water, one of the major English chemical 
companies (in 1959) stopped production of arsenical sprays and called in supplies already in the 
hands of dealers, and shortly thereafter the Ministry of Agriculture announced that because of 
high risks to people and cattle restrictions on the use of arsenites would be imposed. In 1961, 
the Australian government announced a similar ban. No such restrictions impede the use of 
these poisons in the United States, however. 

Some of the 'dinitro' compounds are also used as herbicides. They are rated as among the most 
dangerous materials of this type in use in the United States. Dinitrophenol is a strong metabolic 
stimulant. For this reason it was at one time used as a reducing drug, but the margin between 
the slimming dose and that required to poison or kill was slight— so slight that several patients 
died and many suffered permanent injury before use of the drug was finally halted. A related 
chemical, pentachlorophenol, sometimes known as 'penta', is used as a weed killer as well as 

an insecticide, often being sprayed along railroad tracks and in waste areas. Penta is extremely 
toxic to a wide variety of organisms from bacteria to man. Like the dinitros, it interferes, often 
fatally, with the body's source of energy, so that the affected organism almost literally burns 
itself up. Its fearful power is illustrated in a fatal accident recently reported by the California 
Department of Health. A tank truck driver was preparing a cotton defoliant by mixing diesel oil 
with pentachlorophenol. As he was drawing the concentrated chemical out of a drum, the 
spigot accidentally toppled back. He reached in with his bare hand to regain the spigot. 
Although he washed immediately, he became acutely ill and died the next day. 
While the results of weed killers such as sodium arsenite or the phenols are grossly obvious, 
some other herbicides are more insidious in their effects. For example, the now famous 
cranberry- weed killer aminotriazole, or amitrol, is rated as having relatively low toxicity. But in 
the long run its tendency to cause malignant tumors of the thyroid may be far more significant 
for wildlife and perhaps also for man. Among the herbicides are some that are classified as 
'mutagens', or agents capable of modifying the genes, the materials of heredity. We are rightly 
appalled by the genetic effects of radiation; how then, can we be indifferent to the same effect 
in chemicals that we disseminate widely in our environment? 

4. Surface Waters and Underground Seas 

OF ALL our natural resources water has become the most precious. By far the greater 
part of the earth's surface is covered by its enveloping seas, yet in the midst of this plenty we 
are in want. By a strange paradox, most of the earth's abundant water is not usable for 
agriculture, industry, or human consumption because of its heavy load of sea salts, and so most 
of the world's population is either experiencing or is threatened with critical shortages. In an 
age when man has forgotten his origins and is blind even to his most essential needs for 
survival, water along with other resources has become the victim of his indifference. 
The problem of water pollution by pesticides can be understood only in context, as part of the 
whole to which it belongs— the pollution of the total environment of mankind. The pollution 
entering our waterways comes from many sources: radioactive wastes from reactors, 
laboratories, and hospitals; fallout from nuclear explosions; domestic wastes from cities and 
towns; chemical wastes from factories. To these is added a new kind of fallout— the chemical 
sprays applied to croplands and gardens, forests and fields. Many of the chemical agents in this 
alarming melange imitate and augment the harmful effects of radiation, and within the groups 
of chemicals themselves there are sinister and little understood interactions, transformations, 
and summations of effect. 

Ever since chemists began to manufacture substances that nature never invented, the problems 
of water purification have become complex and the danger to users of water has increased. As 
we have seen, the production of these synthetic chemicals in large volume began in the 1940s. 
It has now reached such proportions that an appalling deluge of chemical pollution is daily 
poured into the nation's waterways. When inextricably mixed with domestic and other wastes 
discharged into the same water, these chemicals sometimes defy detection by the methods in 
ordinary use by purification plants. Most of them are so stable that they cannot be broken 
down by ordinary processes. Often they cannot even be identified. In rivers, a really incredible 
variety of pollutants combine to produce deposits that the sanitary engineers can only 
despairingly refer to as 'gunk'. Professor Rolf Eliassen of the Massachusetts Institute of 
Technology testified before a congressional committee to the impossibility of predicting the 
composite effect of these chemicals, or of identifying the organic matter resulting from the 
mixture. 'We don't begin to know what that is,' said Professor Eliassen. 'What is the effect on 
the people? We don't know.' 

To an ever-increasing degree, chemicals used for the control of insects, rodents, or unwanted 
vegetation contribute to these organic pollutants. Some are deliberately applied to bodies of 
water to destroy plants, insect larvae, or undesired fishes. Some come from forest spraying that 
may blanket two or three million acres of a single state with spray directed against a single 
insect pest— spray that falls directly into streams or that drips down through the leafy canopy 
to the forest floor, there to become part of the slow movement of seeping moisture beginning 
its long journey to the sea. Probably the bulk of such contaminants are the waterborne residues 
of the millions of pounds of agricultural chemicals that have been applied to farmlands for 
insect or rodent control and have been leached out of the ground by rains to become part of 
the universal seaward movement of water. 

Here and there we have dramatic evidence of the presence of these chemicals in our streams 
and even in public water supplies. For example, a sample of drinking water from an orchard 
area in Pennsylvania, when tested on fish in a laboratory, contained enough insecticide to kill all 
of the test fish in only four hours. Water from a stream draining sprayed cotton fields remained 
lethal to fishes even after it had passed through a purifying plant, and in fifteen streams 
tributary to the Tennessee River in Alabama the runoff from fields treated with toxaphene, a 
chlorinated hydrocarbon, killed all the fish inhabiting the streams. Two of these streams were 
sources of municipal water supply. Yet for a week after the application of the insecticide the 
water remained poisonous, a fact attested by the daily deaths of goldfish suspended in cages 

For the most part this pollution is unseen and invisible, making its presence known when 
hundreds or thousands of fish die, but more often never detected at all. The chemist who 
guards water purity has no routine tests for these organic pollutants and no way to remove 
them. But whether detected or not, the pesticides are there, and as might be expected with any 
materials applied to land surfaces on so vast a scale, they have now found their way into many 
and perhaps all of the major river systems of the country. 

If anyone doubts that our waters have become almost universally contaminated with 
insecticides he should study a small report issued by the United States Fish and Wildlife Service 
in 1960. The Service had carried out studies to discover whether fish, like warm-blooded 
animals, store insecticides in their tissues. The first samples were taken from forest areas in the 
West where there had been mass spraying of DDT for the control of the spruce budworm. As 
might have been expected, all of these fish contained DDT. The really significant findings were 
made when the investigators turned for comparison to a creek in a remote area about 30 miles 
from the nearest spraying for budworm control. This creek was upstream from the first and 
separated from it by a high waterfall. No local spraying was known to have occurred. Yet these 
fish, too, contained DDT. Had the chemical reached this remote creek by hidden underground 
streams? Or had it been airborne, drifting down as fallout on the surface of the creek? In still 
another comparative study, DDT was found in the tissues of fish from a hatchery where the 
water supply originated in a deep well. Again there was no record of local spraying. The only 
possible means of contamination seemed to be by means of groundwater. 
In the entire water-pollution problem, there is probably nothing more disturbing than the 
threat of widespread contamination of groundwater. It is not possible to add pesticides to 
water anywhere without threatening the purity of water everywhere. Seldom if ever does 
Nature operate in closed and separate compartments, and she has not done so in distributing 
the earth's water supply. Rain, falling on the land, settles down through pores and cracks in soil 
and rock, penetrating deeper and deeper until eventually it reaches a zone where all the pores 
of the rock are filled with water, a dark, subsurface sea, rising under hills, sinking beneath 
valleys. This groundwater is always on the move, sometimes at a pace so slow that it travels no 
more than 50 feet a year, sometimes rapidly, by comparison, so that it moves nearly a tenth of 
a mile in a day. It travels by unseen waterways until here and there it comes to the surface as a 
spring, or perhaps it is tapped to feed a well. But mostly it contributes to streams and so to 
rivers. Except for what enters streams directly as rain or surface runoff, all the running water of 
the earth's surface was at one time groundwater. And so, in a very real and frightening sense, 
pollution of the groundwater is pollution of water everywhere. . . . 

It must have been by such a dark, underground sea that poisonous chemicals traveled from a 
manufacturing plant in Colorado to a farming district several miles away, there to poison wells, 
sicken humans and livestock, and damage crops— an extraordinary episode that may easily be 
only the first of many like it. Its history, in brief, is this. In 1943, the Rocky Mountain Arsenal of 
the Army Chemical Corps, located near Denver, began to manufacture war materials. Eight 
years later the facilities of the arsenal were leased to a private oil company for the production 
of insecticides. Even before the change of operations, however, mysterious reports had begun 
to come in. Farmers several miles from the plant began to report unexplained sickness among 
livestock; they complained of extensive crop damage. Foliage turned yellow, plants failed to 
mature, and many crops were killed outright. There were reports of human illness, thought by 
some to be related. 

The irrigation waters on these farms were derived from shallow wells. When the well waters 
were examined (in a study in 1959, in which several state and federal agencies participated) 
they were found to contain an assortment of chemicals. Chlorides, chlorates, salts of 
phosphoric acid, fluorides, and arsenic had been discharged from the Rocky Mountain Arsenal 
into holding ponds during the years of its operation. Apparently the groundwater between the 
arsenal and the farms had become contaminated and it had taken 7 to 8 years for the wastes to 
travel underground a distance of about 3 miles from the holding ponds to the nearest farm. 
This seepage had continued to spread and had further contaminated an area of unknown 
extent. The investigators knew of no way to contain the contamination or halt its advance. 
All this was bad enough, but the most mysterious and probably in the long run the most 
significant feature of the whole episode was the discovery of the weed killer 2,4-D in some of 
the wells and in the holding ponds of the arsenal. Certainly its presence was enough to account 
for the damage to crops irrigated with this water. But the mystery lay in the fact that no 2,4-D 
had been manufactured at the arsenal at any stage of its operations. After long and careful 
study, the chemists at the plant concluded that the 2,4-D had been formed spontaneously in 
the open basins. It had been formed there from other substances discharged from the arsenal; 
in the presence of air, water, and sunlight, and quite without the intervention of human 
chemists, the holding ponds had become chemical laboratories for the production of a new 
chemical— a chemical fatally damaging to much of the plant life it touched. And so the story of 
the Colorado farms and their damaged crops assumes a significance that transcends its local 
importance. What other parallels may there be, not only in Colorado but wherever chemical 
pollution finds its way into public waters? In lakes and streams everywhere, in the presence of 
catalyzing air and sunlight, what dangerous substances may be born of parent chemicals 
labeled 'harmless'? 

Indeed one of the most alarming aspects of the chemical pollution of water is the fact that 
here— in river or lake or reservoir, or for that matter in the glass of water served at your dinner 
table— are mingled chemicals that no responsible chemist would think of combining in his 
laboratory. The possible interactions between these freely mixed chemicals are deeply 
disturbing to officials of the United States Public Health Service, who have expressed the fear 
that the production of harmful substances from comparatively innocuous chemicals may be 
taking place on quite a wide scale. The reactions may be between two or more chemicals, or 
between chemicals and the radioactive wastes that are being discharged into our rivers in ever- 
increasing volume. Under the impact of ionizing radiation some rearrangement of atoms could 

easily occur, changing the nature of the chemicals in a way that is not only unpredictable but 
beyond control. It is, of course, not only the groundwaters that are becoming contaminated, 
but surface-moving waters as well— streams, rivers, irrigation waters. A disturbing example of 
the latter seems to be building up on the national wildlife refuges at Tule Lake and Lower 
Klamath, both in California. These refuges are part of a chain including also the refuge on Upper 
Klamath Lake just over the border in Oregon. All are linked, perhaps fatefully, by a shared water 
supply, and all are affected by the fact that they lie like small islands in a great sea of 
surrounding farmlands— land reclaimed by drainage and stream diversion from an original 
waterfowl paradise of marshland and open water. 

These farmlands around the refuges are now irrigated by water from Upper Klamath Lake. The 
irrigation waters, recollected from the fields they have served, are then pumped into Tule Lake 
and from there to Lower Klamath. All of the waters of the wildlife refuges established on these 
two bodies of water therefore represent the drainage of agricultural lands. It is important to 
remember this in connection with recent happenings. In the summer of 1960 the refuge staff 
picked up hundreds of dead and dying birds at Tule Lake and Lower Klamath. Most of them 
were fish-eating species— herons, pelicans, gulls. Upon analysis, they were found to contain 
insecticide residues identified as toxaphene, DDD, and DDE. Fish from the lakes were also found 
to contain insecticides; so did samples of plankton. The refuge manager believes that pesticide 
residues are now building up in the waters of these refuges, being conveyed there by return 
irrigation flow from heavily sprayed agricultural lands. 

Such poisoning of waters set aside for conservation purposes could have consequences felt by 
every western duck hunter and by everyone to whom the sight and sound of drifting ribbons of 
waterfowl across an evening sky are precious. These particular refuges occupy critical positions 
in the conservation of western waterfowl. They lie at a point corresponding to the narrow neck 
of a funnel, into which all the migratory paths composing what is known as the Pacific Flyway 
converge. During the fall migration they receive many millions of ducks and geese from nesting 
grounds extending from the shores of Bering Sea east to Hudson Bay— fully three fourths of all 
the waterfowl that move south into the Pacific Coast states in autumn. In summer they provide 
nesting areas for waterfowl, especially for two endangered species, the redhead and the ruddy 
duck. If the lakes and pools of these refuges become seriously contaminated the da mage to the 
waterfowl populations of the Far West could be irreparable. Water must also be thought of in 
terms of the chains of life it supports— from the small-as-dust green cells of the drifting plant 
plankton, through the minute water fleas to the fishes that strain plankton from the water and 
are in turn eaten by other fishes or by birds, mink, raccoons— in an endless cyclic transfer of 
materials from life to life. We know that the necessary minerals in the water are so passed from 
link to link of the food chains. Can we suppose that poisons we introduce into water will not 
also enter into these cycles of nature? 

The answer is to be found in the amazing history of Clear Lake, California. Clear Lake lies in 
mountainous country some 90 miles north of San Francisco and has long been popular with 
anglers. The name is inappropriate, for actually it is a rather turbid lake because of the soft 
black ooze that covers its shallow bottom. Unfortunately for the fishermen and the resort 
dwellers on its shores, its waters have provided an ideal habitat for a small gnat, Chaoborus 
astictopus. Although closely related to mosquitoes, the gnat is not a bloodsucker and probably 
does not feed at all as an adult. However, human beings who shared its habitat found it 

annoying because of its sheer numbers. Efforts were made to control it but they were largely 
fruitless until, in the late 1940s, the chlorinated hydrocarbon insecticides offered new weapons. 
The chemical chosen for a fresh attack was DDD, a close relative of DDT but apparently offering 
fewer threats to fish life. The new control measures undertaken in 1949 were carefully planned 
and few people would have supposed any harm could result. The lake was surveyed, its volume 
determined, and the insecticide applied in such great dilution that for every part of chemical 
there would be 70 million parts of water. Control of the gnats was at first good, but by 1954 the 
treatment had to be repeated, this time at the rate of 1 part of insecticide in 50 million parts of 
water. The destruction of the gnats was thought to be virtually complete. 
The following winter months brought the first intimation that other life was affected: the 
western grebes on the lake began to die, and soon more than a hundred of them were reported 
dead. At Clear Lake the western grebe is a breeding bird and also a winter visitant, attracted by 
the abundant fish of the lake. It is a bird of spectacular appearance and beguiling habits, 
building its floating nests in shallow lakes of western United States and Canada. It is called the 
'swan grebe' with reason, for it glides with scarcely a ripple across the lake surface, the body 
riding low, white neck and shining black head held high. The newly hatched chick is clothed in 
soft gray down; in only a few hours it takes to the water and rides on the back of the father or 
mother, nestled under the parental wing coverts. 

Following a third assault on the ever-resilient gnat population, in 1957, more grebes died. As 
had been true in 1954, no evidence of infectious disease could be discovered on examination of 
the dead birds. But when someone thought to analyze the fatty tissues of the grebes, they were 
found to be loaded with DDD in the extraordinary concentration of 1600 parts per million. The 
maximum concentration applied to the water was part per million. How could the chemical 
have built up to such prodigious levels in the grebes? These birds, of course, are fish eaters. 
When the fish of Clear Lake also were analyzed the picture began to take form— the poison 
being picked up by the smallest organisms, concentrated and passed on to the larger predators. 
Plankton organisms were found to contain about 5 parts per million of the insecticide (about 25 
times the maximum concentration ever reached in the water itself); plant-eating fishes had 
built up accumulations ranging from 40 to 300 parts per million; carnivorous species had stored 
the most of all. One, a brown bullhead, had the astounding concentration of 2500 parts per 
million. It was a house-that-Jack-built sequence, in which the large carnivores had eaten the 
smaller carnivores, that had eaten the herbivores, that had eaten the plankton, that had 
absorbed the poison from the water. 

Even more extraordinary discoveries were made later. No trace of DDD could be found in the 
water shortly after the last application of the chemical. But the poison had not really left the 
lake; it had merely gone into the fabric of the life the lake supports. Twenty-three months after 
the chemical treatment had ceased, the plankton still contained as much as 5.3 parts per 
million. In that interval of nearly two years, successive crops of plankton had flowered and 
faded away, but the poison, although no longer present in the water, had somehow passed 
from generation to generation. And it lived on in the animal life of the lake as well. All fish, 
birds, and frogs examined a year after the chemical applications had ceased still contained 
DDD. The amount found i n the flesh always exceeded by many times the original concentration 
in the water. Among these living carriers were fish that had hatched nine months after the last 
DDD application, grebes, and California gulls that had built up concentrations of more than 

2000 parts per million. Meanwhile, the nesting colonies of the grebes dwindled— from more 
than 1000 pairs before the first insecticide treatment to about 30 pairs in 1960. And even the 
thirty seem to have nested in vain, for no young grebes have been observed on the lake since 
the last DDD application. 

This whole chain of poisoning, then, seems to rest on a base of minute plants which must have 
been the original concentrators. But what of the opposite end of the food chain— the human 
being who, in probable ignorance of all this sequence of events, has rigged his fishing tackle, 
caught a string of fish from the waters of Clear Lake, and taken them home to fry for his 
supper? What could a heavy dose of DDD, or perhaps repeated doses, do to him? Although the 
California Department of Public Health professed to see no hazard, nevertheless in 1959 it 
required that the use of DDD in the lake be stopped. In view of the scientific evidence of the 
vast biological potency of this chemical, the action seems a minimum safety measure. The 
physiological effect of DDD is probably unique among insecticides, for it destroys part of the 
adrenal gland— the cells of the outer layer known as the adrenal cortex, which secretes the 
hormone cortin. This destructive effect, known since 1948, was at first believed to be confined 
to dogs, because it was not revealed in such experimental animals as monkeys, rats, or rabbits. 
It seemed suggestive, however, that DDD produced in dogs a condition very similar to that 
occurring in man in the presence of Addison's disease. Recent medical research has revealed 
that DDD does strongly suppress the function of the human adrenal cortex. Its cell-destroying 
capacity is now clinically utilized in the treatment of a rare type of cancer which develops in the 
adrenal gland. . . . 

The Clear Lake situation brings up a question that the public needs to face: Is it wise or 
desirable to use substances with such strong effect on physiological processes for the control of 
insects, especially when the control measures involve introducing the chemical directly into a 
body of water? The fact that the insecticide was applied in very low concentrations is 
meaningless, as its explosive progress through the natural food chain in the lake demonstrates. 
Yet Clear Lake is typical of a large and growing number of situations where solution of an 
obvious and often trivial problem creates a far more serious but conveniently less tangible one. 
Here the problem was resolved in favor of those annoyed by gnats, and at the expense of an 
unstated, and probably not even clearly understood, risk to all who took food or water from the 
lake. It is an extraordinary fact that the deliberate introduction of poisons into a reservoir is 
becoming a fairly common practice. The purpose is usually to promote recreational uses, even 
though the water must then be treated at some expense to make it fit for its intended use as 
drinking water. When sportsmen of an area want to 'improve' fishing in a reservoir, they prevail 
on authorities to dump quantities of poison into it to kill the undesired fish, which are then 
replaced with hatchery fish more suited to the sportsmen's taste. The procedure has a strange, 
Alice-in-Wonderland quality. The reservoir was created as a public water supply, yet the 
community, probably unconsulted about the sportsmen's project, is forced either to drink 
water containing poisonous residues or to pay out tax money for treatment of the water to 
remove the poisons— treatments that are by no means foolproof. 

As ground and surface waters are contaminated with pesticides and other chemicals, there is 
danger that not only poisonous but also cancer-producing substances are being introduced into 
public water supplies. Dr. W. C. Hueper of the National Cancer Institute has warned that 'the 
danger of cancer hazards from the consumption of contaminated drinking water will grow 

considerably within the foreseeable future.' And indeed a study made in Holland in the early 
1950s provides support for the view that polluted waterways may carry a cancer hazard. Cities 
receiving their drinking water from rivers had a higher death rate from cancer than did those 
whose water came from sources presumably less susceptible to pollution such as wells. Arsenic, 
the environmental substance most clearly established as causing cancer in man, is involved in 
two historic cases in which polluted water supplies caused widespread occurrence of cancer. In 
one case the arsenic came from the slag heaps of mining operations, in the other from rock 
with a high natural content of arsenic. These conditions may easily be duplicated as a result of 
heavy applications of arsenical insecticides. The soil in such areas becomes poisoned. Rains 
then carry part of the arsenic into streams, rivers, and reservoirs, as well as into the vast 
subterranean seas of groundwater. 

Here again we are reminded that in nature nothing exists alone. To understand more clearly 
how the pollution of our world is happening, we must now look at another of the earth's basic 
resources, the soil. 

5. Realms of the Soil 

THE THIN LAYER of soil that forms a patchy covering over the continents controls our 
own existence and that of every other animal of the land. Without soil, land plants as we know 
them could not grow, and without plants no animals could survive. 

Yet if our agriculture-based life depends on the soil, it is equally true that soil depends on life, 
its very origins and the maintenance of its true nature being intimately related to living plants 
and animals. For soil is in part a creation of life, born of a marvelous interaction of life and 
nonlife long eons ago. The parent materials were gathered together as volcanoes poured them 
out in fiery streams, as waters running over the bare rocks of the continents wore away even 
the hardest granite, and as the chisels of frost and ice split and shattered the rocks. Then living 
things began to work their creative magic and little by little these inert materials became soil. 
Lichens, the rocks' first cove ring, aided the process of disintegration by their acid secretions and 
made a lodging place for other life. Mosses took hold in the little pockets of simple soil— soil 
formed by crumbling bits of lichen, by the husks of minute insect life, by the debris of a fauna 
beginning its emergence from the sea. 

Life not only formed the soil, but other living things of incredible abundance and diversity now 
exist within it; if this were not so the soil would be a dead and sterile thing. By their presence 
and by their activities the myriad organisms of the soil make it capable of supporting the earth's 
green mantle. The soil exists in a state of constant change, taking part in cycles that have no 
beginning and no end. New materials are constantly being contributed as rocks disintegrate, as 
organic matter decays, and as nitrogen and other gases are brought down in rain from the 
skies. At the same time other materials are being taken away, borrowed for temporary use by 
living creatures. Subtle and vastly important chemical changes are constantly in progress, 
converting elements derived from air and water into forms suitable for use by plants. In all 
these changes living organisms are active agents. 

There are few studies more fascinating, and at the same time more neglected, than those of 
the teeming populations that exist in the dark realms of the soil. We know too little of the 
threads that bind the soil organisms to each other and to their world, and to the world above. 
Perhaps the most essential organisms in the soil are the smallest— the invisible hosts of 
bacteria and of threadlike fungi. Statistics of their abundance take us at once into astronomical 
figures. A teaspoonful of topsoil may contain billions of bacteria. In spite of their minute size, 
the total weight of this host of bacteria in the top foot of a single acre of fertile soil may be as 
much as a thousand pounds. Ray fungi, growing in long threadlike filaments, are somewhat less 
numerous than the bacteria, yet because they are larger their total weight in a given amount of 
soil may be about the same. With small green cells called algae, these make up the microscopic 
plant life of the soil. Bacteria, fungi, and algae are the principal agents of decay, reducing plant 
and animal residues to their component minerals. The vast cyclic movements of chemical 
elements such as carbon and nitrogen through soil and air and living tissue could not proceed 
without these microplants. Without the nitrogen-fixing bacteria, for example, plants would 
starve for want of nitrogen, though surrounded by a sea of nitrogen-containing air. Other 
organisms form carbon dioxide, which, as carbonic acid, aids in dissolving rock. Still other soil 

microbes perform various oxidations and reductions by which minerals such as iron, 
manganese, and sulfur are transformed and made available to plants. 

Also present in prodigious numbers are microscopic mites and primitive wingless insects called 
springtails. Despite their small size they play an important part in breaking down the residues of 
plants, aiding in the slow conversion of the litter of the forest floor to soil. The specialization of 
some of these minute creatures for their task is almost incredible. Several species of mites, for 
example, can begin life only within the fallen needles of a spruce tree. Sheltered here, they 
digest out the inner tissues of the needle. When the mites have completed their development 
only the outer layer of cells remains. The truly staggering task of dealing with the tremendous 
amount of plant material in the annual leaf fall belongs to some of the small insects of the soil 
and the forest floor. They macerate and digest the leaves, and aid in mixing the decomposed 
matter with the surface soil. 

Besides all this horde of minute but ceaselessly toiling creatures there are of course many 
larger forms, for soil life runs the gamut from bacteria to mammals. Some are permanent 
residents of the dark subsurface layers; some hibernate or spend definite parts of their life 
cycles in underground chambers; some freely come and go between their burrows and the 
upper world. In general the effect of all this habitation of the soil is to aerate it and improve 
both its drainage and the penetration of water throughout the layers of plant growth. 
Of all the larger inhabitants of the soil, probably none is more important than the earthworm. 
Over three quarters of a century ago, Charles Darwin published a book titled The Formation of 
Vegetable Mould, through the Action of Worms, with Observations on Their Habits. In it he gave 
the world its first understanding of the fundamental role of earthworms as geologic agents for 
the transport of soil— a picture of surface rocks being gradually covered by fine soil brought up 
from below by the worms, in annual amounts running to many tons to the acre in most 
favorable areas. At the same time, quantities of organic matter contained in leaves and grass 
(as much as 20 pounds to the square yard in six months) are drawn down into the burrows and 
incorporated in soil. Darwin's calculations showed that the toil of earthworms might add a layer 
of soil an inch to an inch and a half thick in a ten-year period. And this is by no means all they 
do: their burrows aerate the soil, keep it well drained, and aid the penetration of plant roots. 
The presence of earthworms increases the nitrifying powers of the soil bacteria and decreases 
putrefaction of the soil. Organic matter is broken down as it passes through the digestive tracts 
of the worms and the soil is enriched by their excretory products. This soil community, then, 
consists of a web of interwoven lives, each in some way related to the others— the living 
creatures depending on the soil, but the soil in turn a vital element of the earth only so long as 
this community within it flourishes. 

The problem that concerns us here is one that has received little consideration: What happens 
to these incredibly numerous and vitally necessary inhabitants of the soil when poisonous 
chemicals are carried down into their world, either introduced directly as soil 'sterilants' or 
borne on the rain that has picked up a lethal contamination as it filters through the leaf canopy 
of forest and orchard and cropland? Is it reasonable to suppose that we can apply a broad- 
spectrum insecticide to kill the burrowing larval stages of a crop-destroying insect, for example, 
without also killing the 'good' insects whose function may be the essential one of breaking 
down organic matter? Or can we use a nonspecific fungicide without also killing the fungi that 

inhabit the roots of many trees in a beneficial association that aids the tree in extracting 
nutrients from the soil? 

The plain truth is that this critically important subject of the ecology of the soil has been largely 
neglected even by scientists and almost completely ignored by control men. Chemical control 
of insects seems to have proceeded on the assumption that the soil could and would sustain 
any amount of insult via the introduction of poisons without striking back. The very nature of 
the world of the soil has been largely ignored. From the few studies that have been made, a 
picture of the impact of pesticides on the soil is slowly emerging. It is not surprising that the 
studies are not always in agreement, for soil types vary so enormously that what causes 
damage in one may be innocuous in another. Light sandy soils suffer far more heavily than 
humus types. Combinations of chemicals seem to do more harm than separate applications. 
Despite the varying results, enough solid evidence of harm is accumulating to cause 
apprehension on the part of many scientists. Under some conditions, the chemical conversions 
and transformations that lie at the very heart of the living world are affected. Nitrification, 
which makes atmospheric nitrogen available to plants, is an example. The herbicide 2,4-D 
causes a temporary interruption of nitrification. In recent experiments in Florida, lindane, 
heptachlor, and BHC (benzene hexachloride) reduced nitrification after only two weeks in soil; 
BHC and DDT had significantly detrimental effects a year after treatment. In other experiments 
BHC, aldrin, lindane, heptachlor, and DDD all prevented nitrogen-fixing bacteria from forming 
the necessary root nodules on leguminous plants. A curious but beneficial relation between 
fungi and the roots of higher plants is seriously disrupted. Sometimes the problem is one of 
upsetting that delicate balance of populations by which nature accomplishes far-reaching aims. 
Explosive increases in some kinds of soil organisms have occurred when others have been 
reduced by insecticides, disturbing the relation of predator to prey. Such changes could easily 
alter the metabolic activity of the soil and affect its productivity. They could also mean that 
potentially harmful organisms, formerly held in check, could escape from their natural controls 
and rise to pest status. 

One of the most important things to remember about insecticides in soil is their long 
persistence, measured not in months but in years. Aldrin has been recovered after four years, 
both as traces and more abundantly as converted to dieldrin. Enough toxaphene remains in 
sandy soil ten years after its application to kill termites. Benzene hexachloride persists at least 
eleven years; heptachlor or a more toxic derived chemical, at least nine. Chlordane has been 
recovered twelve years after its application, in the amount of 15 per cent of the original 

Seemingly moderate applications of insecticides over a period of years may build up fantastic 
quantities in soil. Since the chlorinated hydrocarbons are persistent and long-lasting, each 
application is merely added to the quantity remaining from the previous one. The old legend 
that 'a pound of DDT to the acre is harmless' means nothing if spraying is repeated. Potato soils 
have been found to contain up to 15 pounds of DDT per acre, corn soils up to 19. A cranberry 
bog under study contained 34.5 pounds to the acre. Soils from apple orchards seem to reach 
the peak of contamination, with DDT accumulating at a rate that almost keeps pace with its 
rate of annual application. Even in a single season, with orchards sprayed four or more times, 
DDT residues may build up to peaks of 30 to 50 pounds. With repeated spraying over the years 
the range between trees is from 26 to 60 pounds to the acre; under trees, up to 113 pounds. 

Arsenic provides a classic case of the virtually permanent poisoning of the soil. Although arsenic 
as a spray on growing tobacco has been largely replaced by the synthetic organic insecticides 
since the mid-40s, the arsenic content of cigarettes made from American-grown tobacco 
increased more than 300 per cent between the years 1932 and 1952. Later studies have 
revealed increases of as much as 600 per cent. Dr. Henry S. Satterlee, an authority on arsenic 
toxicology, says that although organic insecticides have been largely substituted for arsenic, the 
tobacco plants continue to pick up the old poison, for the soils of tobacco plantations are now 
thoroughly impregnated with residues of a heavy and relatively insoluble poison, arsenate of 
lead. This will continue to release arsenic in soluble form. The soil of a large proportion of the 
land planted to tobacco has been subjected to 'cumulative and well-nigh permanent poisoning', 
according to Dr. Satterlee. Tobacco grown in the eastern Mediterranean countries where 
arsenical insecticides are not used has shown no such increase in arsenic content. 
We are therefore confronted with a second problem. We must not only be concerned with 
what is happening to the soil; we must wonder to what extent insecticides are absorbed from 
contaminated soils and introduced into plant tissues. Much depends on the type of soil, the 
crop, and the nature and concentration of the insecticide. Soil high in organic matter releases 
smaller quantities of poisons than others. Carrots absorb more insecticide than any other crop 
studied; if the chemical used happens to be lindane, carrots actually accumulate higher 
concentrations than are present in the soil. In the future it may become necessary to analyze 
soils for insecticides before planting certain food crops. Otherwise even unsprayed crops may 
take up enough insecticide merely from the soil to render them unfit for market. This very sort 
of contamination has created endless problems for at least one leading manufacturer of baby 
foods who has been unwilling to buy any fruits or vegetables on which toxic insecticides have 
been used. The chemical that caused him the most trouble was benzene hexachloride (BHC), 
which is taken up by the roots and tubers of plants, advertising its presence by a musty taste 
and odor. Sweet potatoes grown on California fields where BHC had been used two years 
earlier contained residues and had to be rejected. In one yea r, in which the firm had contracted 
in South Carolina for its total requirements of sweet potatoes, so large a proportion of the 
acreage was found to be contaminated that the company was forced to buy in the open market 
at a considerable financial loss. Over the years a variety of fruits and vegetables, grown in 
various states, have had to be rejected. The most stubborn problems were concerned with 
peanuts. In the southern states peanuts are usually grown in rotation with cotton, on which 
BHC is extensively used. Peanuts grown later in this soil pick up considerable amounts of the 
insecticide. Actually, only a trace is enough to incorporate the telltale musty odor and taste. 
The chemical penetrates the nuts and cannot be removed. Processing, far from removing the 
mustiness, sometimes accentuates it. The only course open to a manufacturer determined to 
exclude BHC residues is to reject all produce treated with the chemical or grown on soils 
contaminated with it. Sometimes the menace is to the crop itself— a menace that remains as 
long as the insecticide contamination is in the soil. Some insecticides affect sensitive plants such 
as beans, wheat, barley, or rye, retarding root development or depressing growth of seedlings. 
The experience of the hop growers in Washington and Idaho is an example. During the spring of 
1955 many of these growers undertook a large-scale program to control the strawberry root 
weevil, whose larvae had become abundant on the roots of the hops. On the advice of 
agricultural experts and insecticide manufacturers, they chose heptachlor as the control agent. 

Within a year after the heptachlor was applied, the vines in the treated yards were wilting and 
dying. In the untreated fields there was no trouble; the damage stopped at the border between 
treated and untreated fields. The hills were replanted at great expense, but in another year the 
new roots, too, were found to be dead. Four years later the soil still contained heptachlor, and 
scientists were unable to predict how long it would remain poisonous, or to recommend any 
procedure for correcting the condition. The federal Department of Agriculture, which as late as 
March 1959 found itself in the anomalous position of declaring heptachlor to be acceptable for 
use on hops in the form of a soil treatment, belatedly withdrew its registration for such use. 
Meanwhile, the hop growers sought what redress they could in the courts. 
As applications of pesticides continue and the virtually indestructible residues continue to build 
up in the soil, it is almost certain that we are heading for trouble. This was the consensus of a 
group of specialists who met at Syracuse University in 1960 to discuss the ecology of the soil. 
These men summed up the hazards of using 'such potent and little understood tools' as 
chemicals and radiation: 'A few false moves on the part of man may result in destruction of soil 
productivity and the arthropods may well take over.' 

6. Earth's Green Mantle 

WATER, SOIL, and the earth's green mantle of plants make up the world that supports 
the animal life of the earth. 

Although modern man seldom remembers the fact, he could not exist without the plants that 
harness the sun's energy and manufacture the basic foodstuffs he depends upon for life. Our 
attitude toward plants is a singularly narrow one. If we see any immediate utility in a plant we 
foster it. If for any reason we find its presence undesirable or merely a matter of indifference, 
we may condemn it to destruction forthwith. Besides the various plants that are poisonous to 
man or his livestock, or crowd out food plants, many are marked for destruction merely 
because, according to our narrow view, they happen to be in the wrong place at the wrong 
time. Many others are destroyed merely because they happen to be associates of the 
unwanted plants. 

The earth's vegetation is part of a web of life in which there are intimate and essential relations 
between plants and the earth, between plants and other plants, between plants and animals. 
Sometimes we have no choice but to disturb these relationships, but we should do so 
thoughtfully, with full awareness that what we do may have consequences remote in time and 
place. But no such humility marks the booming 'weed killer' business of the present day, in 
which soaring sales and expanding uses mark the production of plant-killing chemicals. One of 
the most tragic examples of our unthinking bludgeoning of the landscape is to be seen in the 
sagebrush lands of the West, where a vast campaign is on to destroy the sage and to substitute 
grasslands. If ever an enterprise needed to be illuminated with a sense of the history and 
meaning of the landscape, it is this. For here the natural landscape is eloquent of the interplay 
of forces that have created it. It is spread before us like the pages of an open book in which we 
can read why the land is what it is, and why we should preserve its integrity. But the pages lie 

The land of the sage is the land of the high western plains and the lower slopes of the 
mountains that rise above them, a land born of the great uplift of the Rocky Mountain system 
many millions of years ago. It is a place of harsh extremes of climate: of long winters when 
blizzards drive down from the mountains and snow lies deep on the plains, of summers whose 
heat is relieved by only scanty rains, with drought biting deep into the soil, and drying winds 
stealing moisture from leaf and stem. As the landscape evolved, there must have been a long 
period of trial and error in which plants attempted the colonization of this high and windswept 
land. One after another must have failed. At last one group of plants evolved which combined 
all the qualities needed to survive. The sage— low-growing and shrubby— could hold its place 
on the mountain slopes and on the plains, and within its small gray leaves it could hold 
moisture enough to defy the thieving winds. It was no accident, but rather the result of long 
ages of experimentation by nature, that the great plains of the West became the land of the 

Along with the plants, animal life, too, was evolving in harmony with the searching 
requirements of the land. In time there were two as perfectly adjusted to their habitat as the 
sage. One was a mammal, the fleet and graceful pronghorn antelope. The other was a bird, the 
sage grouse— the 'cock of the plains' of Lewis and Clark. The sage and the grouse seem made 

for each other. The original range of the bird coincided with the range of the sage, and as the 
sagelands have been reduced, so the populations of grouse have dwindled. The sage is all 
things to these birds of the plains. The low sage of the foothill ranges shelters their nests and 
their young; the denser growths are loafing and roosting areas; at all times the sage provides 
the staple food of the grouse. Yet it is a two-way relationship. The spectacular courtship 
displays of the cocks help loosen the soil beneath and around the sage, aiding invasion by 
grasses which grow in the shelter of sagebrush. The antelope, too, have adjusted their lives to 
the sage. They are primarily animals of the plains, and in winter when the first snows come 
those that have summered in the mountains move down to the lower elevations. There the 
sage provides the food that tides them over the winter. Where all other plants have shed their 
leaves, the sage remains evergreen, the gray-green leaves— bitter, aromatic, rich in proteins, 
fats, and needed minerals— clinging to the stems of the dense and shrubby plants. Though the 
snows pile up, the tops of the sage remain exposed, or can be reached by the sharp, pawing 
hoofs of the antelope. Then grouse feed on them too, finding them on bare and windswept 
ledges or following the antelope to feed where they have scratched away the snow. 
And other life looks to the sage. Mule deer often feed on it. Sage may mean survival for winter- 
grazing livestock. Sheep graze many winter ranges where the big sagebrush forms almost pure 
stands. For half the year it is their principal forage, a plant of higher energy value than even 
alfalfa hay. The bitter upland plains, the purple wastes of sage, the wild, swift antelope, and the 
grouse are then a natural system in perfect balance. Are? The verb must be changed— at least 
in those already vast and growing areas where man is attempting to improve on nature's way. 
In the name of progress the land management agencies have set about to satisfy the insatiable 
demands of the cattlemen for more grazing land. By this they mean grassland— grass without 
sage. So in a land which nature found suited to grass growing mixed with and under the shelter 
of sage, it is now proposed to eliminate the sage and create unbroken grassland. Few seem to 
have asked whether grasslands are a stable and desirable goal in this region. Certainly nature's 
own answer was otherwise. The annual precipitation in this land where the rains seldom fall is 
not enough to support good sod-forming grass; it favors rather the perennial bunchgrass that 
grows in the shelter of the sage. 

Yet the program of sage eradication has been under way for a number of years. Several 
government agencies are active in it; industry has joined with enthusiasm to promote and 
encourage an enterprise which creates expanded markets not only for grass seed but for a large 
assortment of machines for cutting and plowing and seeding. The newest addition to the 
weapons is the use of chemical sprays. Now millions of acres of sagebrush lands are sprayed 
each year. What are the results? The eventual effects of eliminating sage and seeding with 
grass are largely conjectural. Men of long experience with the ways of the land say that in this 
country there is better growth of grass between and under the sage than can possibly be had in 
pure stands, once the moisture-holding sage is gone. But even if the program succeeds in its 
immediate objective, it is clear that the whole closely knit fabric of life has been ripped apart. 
The antelope and the grouse will disappear along with the sage. The deer will suffer, too, and 
the land will be poorer for the destruction of the wild things that belong to it. Even the livestock 
which are the intended beneficiaries will suffer; no amount of lush green grass in summer can 
help the sheep starving in the winter storms for lack of the sage and bitterbrush and other wild 
vegetation of the plains. These are the first and obvious effects. The second is of a kind that is 

always associated with the shotgun approach to nature: the spraying also eliminates a great 
many plants that were not its intended target. Justice William O. Douglas, in his recent book My 
Wilderness: East to Katahdin, has told of an appalling example of ecological destruction 
wrought by the United States Forest Service in the Bridger National Forest in Wyoming. Some 
10,000 acres of sagelands were sprayed by the Service, yielding to pressure of cattlemen for 
more grasslands. The sage was killed, as intended. But so was the green, lifegiving ribbon of 
willows that traced its way across these plains, following the meandering streams. Moose had 
lived in these willow thickets, for willow is to the moose what sage is to the antelope. Beaver 
had lived there, too, feeding on the willows, felling them and making a strong dam across the 
tiny stream. Through the labor of the beavers, a lake backed up. Trout in the mountain streams 
seldom were more than six inches long; in the lake they thrived so prodigiously that many grew 
to five pounds. Waterfowl were attracted to the lake, also. Merely because of the presence of 
the willows and the beavers that depended on them, the region was an attractive recreational 
area with excellent fishing and hunting. 

But with the 'improvement' instituted by the Forest Service, the willows went the way of the 
sagebrush, killed by the same impartial spray. When Justice Douglas visited the area in 1959, 
the year of the spraying, he was shocked to see the shriveled and dying willows— the 'vast, 
incredible damage'. What would become of the moose? Of the beavers and the little world 
they had constructed? A year later he returned to read the answers in the devastated 
landscape. The moose were gone and so were the beaver. Their principal dam had gone out for 
want of attention by its skilled architects, and the lake had drained away. None of the large 
trout were left. None could live in the tiny creek that remained, threading its way through a 
bare, hot land where no shade remained. The living world was shattered. . . . 
Besides the more than four million acres of rangelands sprayed each year, tremendous areas of 
other types of land are also potential or actual recipients of chemical treatments for weed 
control. For example, an area larger than all of New England— some 50 million acres— is under 
management by utility corporations and much of it is routinely treated for 'brush control'. In 
the Southwest an estimated 75 million acres of mesquite lands require management by some 
means, and chemical spraying is the method most actively pushed. An unknown but very large 
acreage of timber-producing lands is now aerially sprayed in order to 'weed out' the hardwoods 
from the more spray-resistant conifers. Treatment of agricultural lands with herbicides doubled 
in the decade following 1949, totaling 53 million acres in 1959. And the combined acreage of 
private lawns, parks, and golf courses now being treated must reach an astronomical figure. 
The chemical weed killers are a bright new toy. They work in a spectacular way; they give a 
giddy sense of power over nature to those who wield them, and as for the long-range and less 
obvious effects— these are easily brushed aside as the baseless imaginings of pessimists. The 
'agricultural engineers' speak blithely of 'chemical plowing' in a world that is urged to beat its 
plowshares into spray guns. The town fathers of a thousand communities lend willing ears to 
the chemical salesman and the eager contractors who will rid the roadsides of 'brush'— for a 
price. It is cheaper than mowing, is the cry. So, perhaps, it appears in the neat rows of figures in 
the official books; but were the true costs entered, the costs not only in dollars but in the many 
equally valid debits we shall presently consider, the wholesale broadcasting of chemicals would 
be seen to be more costly in dollars as well as infinitely damaging to the long-range health of 
the landscape and to all the varied interests that depend on it. 

Take, for instance, that commodity prized by every chamber of commerce throughout the 
land— the good will of vacationing tourists. There is a steadily growing chorus of outraged 
protest about the disfigurement of once beautiful roadsides by chemical sprays, which 
substitute a sere expanse of brown, withered vegetation for the beauty of fern and wild flower, 
of native shrubs adorned with blossom or berry. 'We are making a dirty, brown, dying-looking 
mess along the sides of our roads,' a New England woman wrote angrily to her newspaper. 'This 
is not what the tourists expect, with all the money we are spending advertising the beautiful 

In the summer of 1960 conservationists from many states converged on a peaceful Maine 
island to witness its presentation to the National Audubon Society by its owner, Millicent Todd 
Bingham. The focus that day was on the preservation of the natural landscape and of the 
intricate web of life whose interwoven strands lead from microbes to man. But in the 
background of all the conversations among the visitors to the island was indignation at the 
despoiling of the roads they had traveled. Once it had been a joy to follow those roads through 
the evergreen forests, roads lined with bayberry and sweet fern, alder and huckleberry. Now all 
was brown desolation. One of the conservationists wrote of that August pilgrimage to a Maine 
island: 'I returned. ..angry at the desecration of the Maine roadsides. Where, in previous years, 
the highways were bordered with wildflowers and attractive shrubs, there were only the scars 
of dead vegetation for mile after mile. ..As an economic proposition, can Maine afford the loss 
of tourist goodwill that such sights induce?' Maine roadsides are merely one example, though a 
particularly sad one for those of us who have a deep love for the beauty of that state, of the 
senseless destruction that is going on in the name of roadside brush control throughout the 

Botanists at the Connecticut Arboretum declare that the elimination of beautiful native shrubs 
and wildflowers has reached the proportions of a 'roadside crisis'. Azaleas, mountain laurel, 
blueberries, huckleberries, viburnums, dogwood, bayberry, sweet fern, low shadbush, 
winterberry, chokecherry, and wild plum are dying before the chemical barrage. So are the 
daisies, black-eyed Susans, Queen Anne's lace, goldenrods, and fall asters which lend grace and 
beauty to the landscape. The spraying is not only improperly planned but studded with abuses 
such as these. In a southern New England town one contractor finished his work with some 
chemical remaining in his tank. He discharged this along woodland roadsides where no spraying 
had been authorized. As a result the community lost the blue and golden beauty of its autumn 
roads, where asters and goldenrod would have made a display worth traveling far to see. In 
another New England community a contractor changed the state specifications for town 
spraying without the knowledge of the highway department and sprayed roadside vegetation 
to a height of eight feet instead of the specified maximum of four feet, leaving a broad, 
disfiguring, brown swath. In a Massachusetts community the town officials purchased a weed 
killer from a zealous chemical salesman, unaware that it contained arsenic. One result of the 
subsequent roadside spraying was the death of a dozen cows from arsenic poisoning. 
Trees within the Connecticut Arboretum Natural Area were seriously injured when the town of 
Waterford sprayed the roadsides with chemical weed killers in 1957. Even large trees not 
directly sprayed were affected. The leaves of the oaks began to curl and turn brown, although it 
was the season for spring growth. Then new shoots began to be put forth and grew with 
abnormal rapidity, giving a weeping appearance to the trees. Two seasons later, large branches 

on these trees had died, others were without leaves, and the deformed, weeping effect of 
whole trees persisted. I know well a stretch of road where nature's own landscaping has 
provided a border of alder, viburnum, sweet fern, and juniper with seasonally changing accents 
of bright flowers, or of fruits hanging in jeweled clusters in the fall. The road had no heavy load 
of traffic to support; there were few sharp curves or intersections where brush could obstruct 
the driver's vision. But the sprayers took over and the miles along that road became something 
to be traversed quickly, a sight to be endured with one's mind closed to thoughts of the sterile 
and hideous world we are letting our technicians make. But here and there authority had 
somehow faltered and by an unaccountable oversight there were oases of beauty in the midst 
of austere and regimented control— oases that made the desecration of the greater part of the 
road the more unbearable. In such places my spirit lifted to the sight of the drifts of white 
clover or the clouds of purple vetch with here and there the flaming cup of a wood lily. 
Such plants are 'weeds' only to those who make a business of selling and applying chemicals. In 
a volume of Proceedings of one of the weed-control conferences that are now regular 
institutions, I once read an extraordinary statement of a weed killer's philosophy. The author 
defended the killing of good plants 'simply because they are in bad company.' Those who 
complain about killing wildflowers along roadsides reminded him, he said, of antivivisectionists 
'to whom, if one were to judge by their actions, the life of a stray dog is more sacred than the 
lives of children.' To the author of this paper, many of us would unquestionably be suspect, 
convicted of some deep perversion of character because we prefer the sight of the vetch and 
the clover and the wood lily in all their delicate and transient beauty to that of roadsides 
scorched as by fire, the shrubs brown and brittle, the bracken that once lifted high its 
proudlacework now withered and drooping. We would seem deplorably weak that we can 
tolerate the sight of such 'weeds', that we do not rejoice in their eradication, that we are not 
filled with exultation that man has once more triumphed over miscreant nature. 
Justice Douglas tells of attending a meeting of federal field men who were discussing protests 
by citizens against plans for the spraying of sagebrush that I mentioned earlier in this chapter. 
These men considered it hilariously funny that an old lady had opposed the plan because the 
wildflowers would be destroyed. 'Yet, was not her right to search out a banded cup or a tiger 
lily as inalienable as the right of stockmen to search out grass or of a lumberman to claim a 
tree?' asks this humane and perceptive jurist. 'The esthetic values of the wilderness are as 
much our inheritance as the veins of copper and gold in our hills and the forests in our 
mountains.' There is of course more to the wish to preserve our roadside vegetation than even 
such esthetic considerations. In the economy of nature the natural vegetation has its essential 
place. Hedgerows along country roads and bordering fields provide food, cover, and nesting 
areas for birds and homes for many small animals. Of some 70 species of shrubs and vines that 
are typical roadside species in the eastern states alone, about 65 are important to wildlife as 
food. Such vegetation is also the habitat of wild bees and other pollinating insects. Man is more 
dependent on these wild pollinators than he usually realizes. Even the farmer himself seldom 
understands the value of wild bees and often participates in the very measures that rob him of 
their services. Some agricultural crops and many wild plants are partly or wholly dependent on 
the services of the native pollinating insects. Several hundred species of wild bees take part in 
the pollination of cultivated crops— 100 species visiting the flowers of alfalfa alone. Without 
insect pollination, most of the soil-holding and soil-enriching plants of uncultivated areas would 

die out, with far-reaching consequences to the ecology of the whole region. Many herbs, 
shrubs, and trees of forests and range depend on native insects for their reproduction; without 
these plants many wild animals and range stock would find little food. Now clean cultivation 
and the chemical destruction of hedgerows and weeds are eliminating the last sanctuaries of 
these pollinating insects and breaking the threads that bind life to life. 

These insects, so essential to our agriculture and indeed to our landscape as we know it, 
deserve something better from us than the senseless destruction of their habitat. Honeybees 
and wild bees depend heavily on such 'weeds' as goldenrod, mustard, and dandelions for pollen 
that serves as the food of their young. Vetch furnishes essential spring forage for bees before 
the alfalfa is in bloom, tiding them over this early season so that they are ready to pollinate the 
alfalfa. In the fall they depend on goldenrod at a season when no other food is available, to 
stock up for the winter. By the precise and delicate timing that is nature's own, the emergence 
of one species of wild bees takes place on the very day of the opening of the willow blossoms. 
There is no dearth of men who understand these things, but these are not the men who order 
the wholesale drenching of the landscape with chemicals. 

And where are the men who supposedly understand the value of proper habitat for the 
preservation of wildlife? Too many of them are to be found defending herbicides as 'harmless' 
to wildlife because they are thought to be less toxic than insecticides. Therefore, it is said, no 
harm is done. But as the herbicides rain down on forest and field, on marsh and rangeland, they 
are bringing about marked changes and even permanent destruction of wildlife habitat. To 
destroy the homes and the food of wildlife is perhaps worse in the long run than direct killing. 
The irony of this all-out chemical assault on roadsides and utility rights-of-way is twofold. It is 
perpetuating the problem it seeks to correct, for as experience has clearly shown, the blanket 
application of herbicides does not permanently control roadside 'brush' and the spraying has to 
be repeated year after year. And as a further irony, we persist in doing this despite the fact that 
a perfectly sound method of selective spraying is known, which can achieve long-term 
vegetational control and eliminate repeated spraying in most types of vegetation. The object of 
brush control along roads and rights-of-way is not to sweep the land clear of everything but 
grass; it is, rather, to eliminate plants ultimately tall enough to present an obstruction to 
drivers' vision or interference with wires on rights-of-way. This means, in general, trees. Most 
shrubs are low enough to present no hazard; so, certainly, are ferns and wildflowers. 
Selective spraying was developed by Dr. Frank Egler during a period of years at the American 
Museum of Natural History as director of a Committee for Brush Control Recommendations for 
Rights-of-Way. It took advantage of the inherent stability of nature, building on the fact that 
most communities of shrubs are strongly resistant to invasion by trees. By comparison, 
grasslands are easily invaded by tree seedlings. The object of selective spraying is not to 
produce grass on roadsides and rights-of-way but to eliminate the tall woody plants by direct 
treatment and to preserve all other vegetation. One treatment may be sufficient, with a 
possible follow-up for extremely resistant species; thereafter the shrubs assert control and the 
trees do not return. The best and cheapest controls for vegetation are not chemicals but other 

The method has been tested in research areas scattered throughout the eastern United States. 
Results show that once properly treated, an area becomes stabilized, requiring no respraying 
for at least 20 years. The spraying can often be done by men on foot, using knapsack sprayers, 

and having complete control over their material. Sometimes compressor pumps and material 
can be mounted on truck chassis, but there is no blanket spraying. Treatment is directed only to 
trees and any exceptionally tall shrubs that must be eliminated. The integrity of the 
environment is thereby preserved, the enormous value of the wildlife habitat remains intact, 
and the beauty of shrub and fern and wildflower has not been sacrificed. Here and there the 
method of vegetation management by selective spraying has been adopted. For the most part, 
entrenched custom dies hard and blanket spraying continues to thrive, to exact its heavy 
annual costs from the taxpayer, and to inflict its damage on the ecological web of life. It thrives, 
surely, only because the facts are not known. When taxpayers understand that the bill for 
spraying the town roads should come due only once a generation instead of once a year, they 
will surely rise up and demand a change of method. 

Among the many advantages of selective spraying is the fact that it minimizes the amount of 
chemical applied to the landscape. There is no broadcasting of material but, rather, 
concentrated application to the base of the trees. The potential harm to wildlife is therefore 
kept to a minimum. The most widely used herbicides are 2,4-D, 2,4,5-T, and related 
compounds. Whether or not these are actually toxic is a matter of controversy. People spraying 
their lawns with 2,4-D and becoming wet with spray have occasionally developed severe 
neuritis and even paralysis. Although such incidents are apparently uncommon, medical 
authorities advise caution in use of such compounds. Other hazards, more obscure, may also 
attend the rise of 2,4-D. It has been shown experimentally to disturb the basic physiological 
process of respiration in the cell, and to imitate X-rays in damaging the chromosomes. Some 
very recent work indicates that reproduction of birds may be adversely affected by these and 
certain other herbicides at levels far below those that cause death. Apart from any directly toxic 
effects, curious indirect results follow the use of certain herbicides. It has been found that 
animals, both wild herbivores and livestock, are sometimes strangely attracted to a plant that 
has been sprayed, even though it is not one of their natural foods. If a highly poisonous 
herbicide such as arsenic has been used, this intense desire to reach the wilting vegetation 
inevitably has disastrous results. Fatal results may follow, also, from less toxic herbicides if the 
plant itself happens to be poisonous or perhaps to possess thorns or burs. Poisonous range 
weeds, for example, have suddenly become attractive to livestock after spraying, and the 
animals have died from indulging this unnatural appetite. The literature of veterinary medicine 
abounds in similar examples: swine eating sprayed cockleburs with consequent severe illness, 
lambs eating sprayed thistles, bees poisoned by pasturing on mustard sprayed after it came 
into bloom. Wild cherry, the leaves of which are highly poisonous, has exerted a fatal attraction 
for cattle once its foliage has been sprayed with 2,4-D. Apparently the wilting that follows 
spraying (or cutting) makes the plant attractive. Ragwort has provided other examples. 
Livestock ordinarily avoid this plant unless forced to turn to it in late winter and early spring by 
lack of other forage. However, the animals eagerly feed on it after its foliage has been sprayed 
with 2,4-D. The explanation of this peculiar behavior sometimes appears to lie in the changes 
which the chemical brings about in the metabolism of the plant itself. There is temporarily a 
marked increase in sugar content, making the plant more attractive to many animals. 
Another curious effect of 2,4-D has important effects for livestock, wildlife, and apparently for 
men as well. Experiments carried out about a decade ago showed that after treatment with this 
chemical there is a sharp increase in the nitrate content of corn and of sugar beets. The same 

effect was suspected in sorghum, sunflower, spiderwort, lambs quarters, pigweed, and 
smartweed. Some of these are normally ignored by cattle, but are eaten with relish after 
treatment with 2,4-D. A number of deaths among cattle have been traced to sprayed weeds, 
according to some agricultural specialists. The danger lies in the increase in nitrates, for the 
peculiar physiology of the ruminant at once poses a critical problem. Most such animals have a 
digestive system of extraordinary complexity, including a stomach divided into four chambers. 
The digestion of cellulose is accomplished through the action of micro-organisms (rumen 
bacteria) in one of the chambers. When the animal feeds on vegetation containing an 
abnormally high level of nitrates, the micro-organisms in the rumen act on the nitrates to 
change them into highly toxic nitrites. Thereafter a fatal chain of events ensues: the nitrites act 
on the blood pigment to form a chocolate-brown substance in which the oxygen is so firmly 
held that it cannot take part in respiration, hence oxygen is not transferred from the lungs to 
the tissues. Death occurs within a few hours from anoxia, or lack of oxygen. The various reports 
of livestock losses after grazing on certain weeds treated with 2,4-D therefore have a logical 
explanation. The same danger exists for wild animals belonging to the group of ruminants, such 
as deer, antelope, sheep, and goats. Although various factors (such as exceptionally dry 
weather) can cause an increase in nitrate content, the effect of the soaring sales and 
applications of 2,4-D cannot be ignored. The situation was considered important enough by the 
University of Wisconsin Agricultural Experiment Station to justify a warning in 1957 that 'plants 
killed by 2,4-D may contain large amounts of nitrate.' The hazard extends to human beings as 
well as animals and may help to explain the recent mysterious increase in 'silo deaths'. When 
corn, oats, or sorghum containing large amounts of nitrates are ensiled they release poisonous 
nitrogen oxide gases, creating a deadly hazard to anyone entering the silo. Only a few breaths 
of one of these gases can cause a diffuse chemical pneumonia. In a series of such cases studied 
by the University of Minnesota Medical School all but one terminated fatally. . .. 
'Once again we are walking in nature like an elephant in the china cabinet.' So C. J. Briejer, a 
Dutch scientist of rare understanding, sums up our use of weed killers. 'In my opinion too much 
is taken for granted. We do not know whether all weeds in crops are harmful or whether some 
of them are useful,' says Dr. Briejer. Seldom is the question asked, What is the relation between 
the weed and the soil? Perhaps, even from our narrow standpoint of direct self-interest, the 
relation is a useful one. As we have seen, soil and the living things in and upon it exist in a 
relation of interdependence and mutual benefit. Presumably the weed is taking something 
from the soil; perhaps it is also contributing something to it. A practical example was provided 
recently by the parks in a city in Holland. The roses were doing badly. Soil samples showed 
heavy infestations by tiny nematode worms. Scientists of the Dutch Plant Protection Service did 
not recommend chemical sprays or soil treatments; instead, they suggested that marigolds be 
planted among the roses. This plant, which the purist would doubtless consider a weed in any 
rose bed, releases an excretion from its roots that kills the soil nematodes. The advice was 
taken; some beds were planted with ma rigolds, some left without as controls. The results were 
striking. With the aid of the ma rigolds the roses flourished; in the control beds they were sickly 
and drooping. Marigolds are now used in many places for combating nematodes. In the same 
way, and perhaps quite unknown to us, other plants that we ruthlessly eradicate may be 
performing a function that is necessary to the health of the soil. One very useful function of 
natural plant communities— now pretty generally stigmatized as 'weeds'— is to serve as an 

indicator of the condition of the soil. This useful function is of course lost where chemical weed 
killers have been used. Those who find an answer to all problems in spraying also overlook a 
matter of great scientific importance— the need to preserve some natural plant communities. 
We need these as a standard against which we can measure the changes our own activities 
bring about. We need them as wild habitats in which original populations of insects and other 
organisms can be maintained, for, as will be explained in Chapter 16, the development of 
resistance to insecticides is changing the genetic factors of insects and perhaps other 
organisms. One scientist has even suggested that some sort of 'zoo' should be established to 
preserve insects, mites, and the like, before their genetic composition is further changed. Some 
experts warn of subtle but far-reaching vegetational shifts as a result of the growing use of 
herbicides. The chemical 2,4-D, by killing out the broad-leaved plants, allows the grasses to 
thrive in the reduced competition— now some of the grasses themselves have become 'weeds', 
presenting a new problem in control and giving the cycle another turn. This strange situation is 
acknowledged in a recent issue of a journal devoted to crop problems: 'With the widespread 
use of 2,4-D to control broadleaved weeds, grass weeds in particular have increasingly become 
a threat to corn and soybean yields.' 

Ragweed, the bane of hay fever sufferers, offers an interesting example of the way efforts to 
control nature sometimes boomerang. Many thousands of gallons of chemicals have been 
discharged along roadsides in the name of ragweed control. But the unfortunate truth is that 
blanket spraying is resulting in more ragweed, not less. Ragweed is an annual; its seedlings 
require open soil to become established each year. Our best protection against this plant is 
therefore the maintenance of dense shrubs, ferns, and other perennial vegetation. Spraying 
frequently destroys this protective vegetation and creates open, barren areas which the 
ragweed hastens to fill. It is probable, moreover, that the pollen content of the atmosphere is 
not related to roadside ragweed, but to the ragweed of city lots and fallow fields. The booming 
sales of chemical crabgrass killers are another example of how readily unsound methods catch 
on. There is a cheaper and better way to remove crabgrass than to attempt year after year to 
kill it out with chemicals. This is to give it competition of a kind it cannot survive, the 
competition of other grass. Crabgrass exists only in an unhealthy lawn. It is a symptom, not a 
disease in itself. By providing a fertile soil and giving the desired grasses a good start, it is 
possible to create an environment in which crabgrass cannot grow, for it requires open space in 
which it can start from seed year after year. 

Instead of treating the basic condition, suburbanites— advised by nurserymen who in turn have 
been advised by the chemical manufacturers— continue to apply truly astonishing amounts of 
crabgrass killers to their lawns each year. Marketed under trade names which give no hint of 
their nature, many of these preparations contain such poisons as mercury, arsenic, and 
chlordane. Application at the recommended rates leaves tremendous amounts of these 
chemicals on the lawn. Users of one product, for example, apply 60 pounds of technical 
chlordane to the acre if they follow directions. If they use another of the many available 
products, they are applying 175 pounds of metallic arsenic to the acre. The toll of dead birds, as 
we shall see in Chapter 8, is distressing. How lethal these lawns may be for human beings is 
unknown. The success of selective spraying for roadside and right-of-way vegetation, where it 
has been practiced, offers hope that equally sound ecological methods may be developed for 
other vegetation programs for farms, forests, and ranges— methods aimed not at destroying a 

particular species but at managing vegetation as a living community. Other solid achievements 
show what can be done. Biological control has achieved some of its most spectacular successes 
in the area of curbing unwanted vegetation. Nature herself has met many of the problems that 
now beset us, and she has usually solved them in her own successful way. Where man has been 
intelligent enough to observe and to emulate Nature he, too, is often rewarded with success. 
An outstanding example in the field of controlling unwanted plants is the handling of the 
Klamath-weed problem in California. Although the Klamath weed, or goatweed, is a native of 
Europe (where it is called St. Johnswort), it accompanied man in his westward migrations, first 
appearing in the United States in 1793 near Lancaster, Pennsylvania. By 1900 it had reached 
California in the vicinity of the Klamath River, hence the name locally given to it. By 1929 it had 
occupied about 100,000 acres of rangeland, and by 1952 it had invaded some two and one half 
million acres. 

Klamath weed, quite unlike such native plants as sagebrush, has no place in the ecology of the 
region, and no animals or other plants require its presence. On the contrary, wherever it 
appeared livestock became 'scabby, sore-mouthed, and unthrifty' from feeding on this toxic 
plant. Land values declined accordingly, for the Klamath weed was considered to hold the first 
mortgage. In Europe the Klamath weed, or St. Johnswort, has never become a problem because 
along with the plant there have developed various species of insects; these feed on it so 
extensively that its abundance is severely limited. In particular, two species of beetles in 
southern France, pea-sized and of metallic colour have their whole beings so adapted to the 
presence of the weed that they feed and reproduce only upon it. It was an event of historic 
importance when the first shipments of these beetles were brought to the United States in 
1944, for this was the first attempt in North America to control a plant with a plant-eating 
insect. By 1948 both species had become so well established that no further importations were 
needed. Their spread was accomplished by collecting beetle from the original colonies and 
redistributing them at the rate of millions a year. Within small areas the beetles accomplish 
their own dispersion, moving on as soon as the Klamath weed dies out and locating new stands 
with great precision. And as the beetles thin out the weed, desirable range plants that have 
been crowded out are able to return. A ten-year survey completed in 1959 showed that control 
of the Klamath weed had been 'more effective than hoped for even by enthusiasts', with the 
weed reduced to a mere 1 per cent of its former abundance. This token infestation is harmless 
and is actually needed in order to maintain a population of beetles as protection against a 
future increase in the weed. 

Another extraordinarily successful and economical example of weed control may be found in 
Australia. With the colonists' usual taste for carrying plants or animals into a new country, a 
Captain Arthur Phillip had brought various species of cactus into Australia about 1787, 
intending to use them in culturing cochineal insects for dye. Some of the cacti or prickly pears 
escaped from his gardens and by 1925 about 20 species could be found growing wild. Having no 
natural controls in this new territory, they spread prodigiously, eventually occupying about 60 
million acres. At least half of this land was so densely covered as to be useless. In 1920 
Australian entomologists were sent to North and South America to study insect enemies of the 
prickly pears in their native habitat. After trials of several species, 3 billion eggs of an Argentine 
moth were released in Australia in 1930. Seven years later the last dense growth of the prickly 
pear had been destroyed and the once uninhabitable areas reopened to settlement and 

grazing. The whole operation had cost less than a penny per acre. In contrast, the 
unsatisfactory attempts at chemical control in earlier years had cost about £10 per acre. 
Both of these examples suggest that extremely effective control of many kinds of unwanted 
vegetation might be achieved by paying more attention to the role of plant-eating insects. The 
science of range management has largely ignored this possibility, although these insects are 
perhaps the most selective of all grazers and their highly restricted diets could easily be turned 
to man's advantage. 

7. Needless Havoc 

AS MAN PROCEEDS toward his announced goal of the conquest of nature, he has 
written a depressing record of destruction, directed not only against the earth he inhabits but 
against the life that shares it with him. The history of the recent centuries has its black 
passages— the slaughter of the buffalo on the western plains, the massacre of the shorebirds by 
the market gunners, the near-extermination of the egrets for their plumage. Now, to these and 
others like them, we are adding a new chapter and a new kind of havoc— the direct killing of 
birds, mammals, fishes, and indeed practically every form of wildlife by chemical insecticides 
indiscriminately sprayed on the land. Under the philosophy that now seems to guide our 
destinies, nothing must get in the way of the man with the spray gun. The incidental victims of 
his crusade against insects count as nothing; if robins, pheasants, raccoons, cats, or even 
livestock happen to inhabit the same bit of earth as the target insects and to be hit by the rain 
of insect-killing poisons no one must protest. 

The citizen who wishes to make a fair judgment of the question of wildlife loss is today 
confronted with a dilemma. On the one hand conservationists and many wildlife biologists 
assert that the losses have been severe and in some cases even catastrophic. On the other hand 
the control agencies tend to deny flatly and categorically that such losses have occurred, or that 
they are of any importance if they have. Which view are we to accept? The credibility of the 
witness is of first importance. The professional wildlife biologist on the scene is certainly best 
qualified to discover and interpret wildlife loss. The entomologist, whose specialty is insects, is 
not so qualified by training, and is not psychologically disposed to look for undesirable side 
effects of his control program. Yet it is the control men in state and federal governments— and 
of course the chemical manufacturers— who steadfastly deny the facts reported by the 
biologists and declare they see little evidence of harm to wildlife. Like the priest and the Levite 
in the biblical story, they choose to pass by on the other side and to see nothing. Even if we 
charitably explain their denials as due to the shortsightedness of the specialist and the man 
with an interest this does not mean we must accept them as qualified witnesses. 
The best way to form our own judgment is to look at some of the major control programs and 
learn, from observers familiar with the ways of wildlife, and unbiased in favor of chemicals, just 
what has happened in the wake of a rain of poison falling from the skies into the world of 
wildlife. To the bird watcher, the suburbanite who derives joy from birds in his garden, the 
hunter, the fisherman or the explorer of wild regions, anything that destroys the wildlife of an 
area for even a single year has deprived him of pleasure to which he has a legitimate right. This 
is a valid point of view. Even if, as has sometimes happened, some of the birds and mammals 
and fishes are able to re-establish themselves after a single spraying, a great and real harm has 
been done. But such reestablishment is unlikely to happen. Spraying tends to be repetitive, and 
a single exposure from which the wildlife populations might have a chance to recover is a rarity. 
What usually results is a poisoned environment, a lethal trap in which not only the resident 
populations succumb but those who come in as migrants as well. The larger the area sprayed 
the more serious the harm, because no oases of safety remain. Now, in a decade marked by 
insect-control programs in which many thousands or even millions of acres are sprayed as a 
unit, a decade in which private and community spraying has also surged steadily upward, a 

record of destruction and death of American wildlife has accumulated. Let us look at some of 
these programs and see what has happened. 

During the fall of 1959 some 27,000 acres in southeastern Michigan, including numerous 
suburbs of Detroit, were heavily dusted from the air with pellets of aldrin, one of the most 
dangerous of all the chlorinated hydrocarbons. The program was conducted by the Michigan 
Department of Agriculture with the cooperation of the United States Department of 
Agriculture; its announced purpose was control of the Japanese beetle. Little need was shown 
for this drastic and dangerous action. On the contrary, Walter P. Nickell, one of the best-known 
and best-informed naturalists in the state, who spends much of his time in the field with long 
periods in southern Michigan every summer, declared: 'For more than thirty years, to my direct 
knowledge, the Japanese beetle has been present in the city of Detroit in small numbers. The 
numbers have not shown any appreciable increase in all this lapse of years. I have yet to see a 
single Japanese beetle [in 1959] other than the few caught in Government catch traps in 
Detroit. ..Everything is being kept so secret that I have not yet been able to obtain any 
information whatsoever to the effect that they have increased in numbers.' An official release 
by the state agency merely declared that the beetle had 'put in its appearance' in the areas 
designated for the aerial attack upon it. Despite the lack of justification the program was 
launched, with the state providing the manpower and supervising the operation, the federal 
government providing equipment and additional men, and the communities paying for the 
insecticide. The Japanese beetle, an insect accidentally imported into the United States, was 
discovered in New Jersey in 1916, when a few shiny beetles of a metallic green color were seen 
in a nursery near Riverton. The beetles, at first unrecognized, were finally identified as a 
common inhabitant of the main islands of Japan. Apparently they had entered the United 
States on nursery stock imported before restrictions were established in 1912. 
From its original point of entrance the Japanese beetle has spread rather widely throughout 
many of the states east of the Mississippi, where conditions of temperature and rainfall are 
suitable for it. Each year some outward movement beyond the existing boundaries of its 
distribution usually takes place. In the eastern areas where the beetles have been longest 
established, attempts have been made to set up natural controls. Where this has been done, 
the beetle populations have been kept at relatively low levels, as many records attest. Despite 
the record of reasonable control in eastern areas, the midwestern states now on the fringe of 
the beetle's range have launched an attack worthy of the most deadly enemy instead of only a 
moderately destructive insect, employing the most dangerous chemicals distributed in a 
manner that exposes large numbers of people, their domestic animals, and all wildlife to the 
poison intended for the beetle. As a result these Japanese beetle programs have caused 
shocking destruction of animal life and have exposed human beings to undeniable hazard. 
Sections of Michigan, Kentucky, Iowa, Indiana, Illinois, and Missouri are all experiencing a rain 
of chemicals in the name of beetle control. The Michigan spraying was one of the first large- 
scale attacks on the Japanese beetle from the air. The choice of aldrin, one of the deadliest of 
all chemicals, was not determined by any peculiar suitability for Japanese beetle control, but 
simply by the wish to save money— aldrin was the cheapest of the compounds available. While 
the state in its official release to the press acknowledged that aldrin is a 'poison', it implied that 
no harm could come to human beings in the heavily populated areas to which the chemical was 
applied. (The official answer to the query 'What precautions should I take?' was 'For you, 

none.') An official of the Federal Aviation Agency was later quoted in the local press to the 
effect that 'this is a safe operation' and a representative of the Detroit Department of Parks and 
Recreation added his assurance that 'the dust is harmless to humans and will not hurt plants or 
pets.' One must assume that none of these officials had consulted the published and readily 
available reports of the United States Public Health Service, the Fish and Wildlife Service, and 
other evidence of the extremely poisonous nature of aldrin. 

Acting under the Michigan pest control law which allows the state to spray indiscriminately 
without notifying or gaining permission of individual landowners, the low-lying planes began to 
fly over the Detroit area. The city authorities and the Federal Aviation Agency were 
immediately besieged by calls from worried citizens. After receiving nearly 800 calls in a single 
hour, the police begged radio and television stations and newspapers to 'tell the watchers what 
they were seeing and advise them it was safe,' according to the Detroit News. The Federal 
Aviation Agency's safety officer assured the public that 'the planes are carefully supervised' and 
'are authorized to fly low.' In a somewhat mistaken attempt to allay fears, he added that the 
planes had emergency valves that would allow them to dump their entire load instantaneously. 
This, fortunately, was not done, but as the planes went about their work the pellets of 
insecticide fell on beetles and humans alike, showers of 'harmless' poison descending on 
people shopping or going to work and on children out from school for the lunch hour. 
Housewives swept the granules from porches and sidewalks, where they are said to have 
'looked like snow'. As pointed out later by the Michigan Audubon Society, 'In the spaces 
between shingles on roofs, in eaves-troughs, in the cracks in bark and twigs, the little white 
pellets of aldrin-and-clay, no bigger than a pin head, were lodged by the millions. ..When the 
snow and rain came, every puddle became a possible death potion.' Within a few days after the 
dusting operation, the Detroit Audubon Society began receiving calls about the birds. According 
to the Society's secretary, Mrs. Ann Boyes, 'The first indication that the people were concerned 
about the spray was a call I received on Sunday morning from a woman who reported that 
coming home from church she saw an alarming number of dead and dying birds. The spraying 
there had been done on Thursday. She said there were no birds at all flying in the area, that she 
had found at least a dozen [dead] in her backyard and that the neighbors had found dead 
squirrels.' All other calls received by Mrs. Boyes that day reported 'a great many dead birds and 
no live ones... People who had maintained bird feeders said there were no birds at all at their 
feeders.' Birds picked up in a dying condition showed the typical symptoms of insecticide 
poisoning— tremoring, loss of ability to fly, paralysis, convulsions. 

Nor were birds the only forms of life immediately affected. A local veterinarian reported that 
his office was full of clients with dogs and cats that had suddenly sickened. Cats, who so 
meticulously groom their coats and lick their paws, seemed to be most affected. Their illness 
took the form of severe diarrhea, vomiting, and convulsions. The only advice the veterinarian 
could give his clients was not to let the animals out unnecessarily, or to wash the paws 
promptly if they did so. (But the chlorinated hydrocarbons cannot be washed even from fruits 
or vegetables, so little protection could be expected from this measure.) 
Despite the insistence of the City-County Health Commissioner that the birds must have been 
killed by 'some other kind of spraying' and that the outbreak of throat and chest irritations that 
followed the exposure to aldrin must have been due to 'something else', the local Health 
Department received a constant stream of complaints. A prominent Detroit internist was called 

upon to treat four of his patients within an hour after they had been exposed while watching 
the planes at work. All had similar symptoms: nausea, vomiting, chills, fever, extreme fatigue, 
and coughing. The Detroit experience has been repeated in many other communities as 
pressure has mounted to combat the Japanese beetle with chemicals. At Blue Island, Illinois, 
hundreds of dead and dying birds were picked up. Data collected by birdbanders here suggest 
that 80 per cent of the songbirds were sacrificed. In Joliet, Illinois, some 3000 acres were 
treated with heptachlor in 1959. According to reports from a local sportsmen's club, the bird 
population within the treated area was 'virtually wiped out'. Dead rabbits, muskrats, opossums, 
and fish were also found in numbers, and one of the local schools made the collection of 
insecticide-poisoned birds a science project. . . . 

Perhaps no community has suffered more for the sake of a beetleless world than Sheldon, in 
eastern Illinois, and adjacent areas in Iroquois County. In 1954 the United States Department of 
Agriculture and the Illinois Agriculture Department began a program to eradicate the Japanese 
beetle along the line of its advance into Illinois, holding out the hope, and indeed the 
assurance, that intensive spraying would destroy the populations of the invading insect. The 
first 'eradication' took place that year, when dieldrin was applied to 1400 acres by air. Another 
2600 acres were treated similarly in 1955, and the task was presumably considered complete. 
But more and more chemical treatments were called for, and by the end of 1961 some 131,000 
acres had been covered. Even in the first years of the program it was apparent that heavy 
losses were occurring among wildlife and domestic animals. The chemical treatments were 
continued, nevertheless, without consultation with either the United States Fish and Wildlife 
Service or the Illinois Game Management Division. (In the spring of 1960, however, officials of 
the federal Department of Agriculture appeared before a congressional committee in 
opposition to a bill that would require just such prior consultation. They declared blandly that 
the bill was unnecessary because cooperation and consultation were 'usual'. These officials 
were quite unable to recall situations where cooperation had not taken place 'at the 
Washington level'. In the same hearings they stated clearly their unwillingness to consult with 
state fish and game departments.) Although funds for chemical control came in never-ending 
streams, the biologists of the Illinois Natural History Survey who attempted to measure the 
damage to wildlife had to operate on a financial shoestring. A mere $1100 was available for the 
employment of a field assistant in 1954 and no special funds were provided in 1955. Despite 
these crippling difficulties, the biologists assembled facts that collectively paint a picture of 
almost unparalleled wildlife destruction— destruction that became obvious as soon as the 
program got underway. 

Conditions were made to order for poisoning insect-eating birds, both in the poisons used and 
in the events set in motion by their application. In the early programs at Sheldon, dieldrin was 
applied at the rate of 3 pounds to the acre. To understand its effect on birds one need only 
remember that in laboratory experiments on quail dieldrin has proved to be about 50 times as 
poisonous as DDT. The poison spread over the landscape at Sheldon was therefore roughly 
equivalent to 150 pounds of DDT per acre! And this was a minimum, because there seems to 
have been some overlapping of treatments along field borders and in corners. As the chemical 
penetrated the soil the poisoned beetle grubs crawled out on the surface of the ground, where 
they remained for some time before they died, attractive to insect-eating birds. Dead and dying 
insects of various species were conspicuous for about two weeks after the treatment. The 

effect on the bird populations could easily have been foretold. Brown thrashers, starlings, 
meadowlarks, grackles, and pheasants were virtually wiped out. Robins were 'almost 
annihilated', according to the biologists' report. Dead earthworms had been seen in numbers 
after a gentle rain; probably the robins had fed on the poisoned worms. For other birds, too, 
the once beneficial rain had been changed, through the evil power of the poison introduced 
into their world, into an agent of destruction. Birds seen drinking and bathing in puddles left by 
rain a few days after the spraying were inevitably doomed. 

The birds that survived may have been rendered sterile. Although a few nests were found in the 
treated area, a few with eggs, none contained young birds. Among the mammals ground 
squirrels were virtually annihilated; their bodies were found in attitudes characteristic of violent 
death by poisoning. Dead muskrats were found in the treated areas, dead rabbits in the fields. 
The fox squirrel had been a relatively common animal in the town; after the spraying it was 
gone. It was a rare farm in the Sheldon area that was blessed by the presence of a cat after the 
war on beetles was begun. Ninety per cent of all the farm cats fell victims to the dieldrin during 
the first season of spraying. This might have been predicted because of the black record of 
these poisons in other places. Cats are extremely sensitive to all insecticides and especially so, it 
seems, to dieldrin. In western Java in the course of the antimalarial program carried out by the 
World Health Organization, many cats are reported to have died. In central Java so many were 
killed that the price of a cat more than doubled. Similarly, the World Health Organization, 
spraying in Venezuela, is reported to have reduced cats to the status of a rare animal. 
In Sheldon it was not only the wild creatures and the domestic companions that were sacrificed 
in the campaign against an insect. Observations on several flocks of sheep and a herd of beef 
cattle are indicative of the poisoning and death that threatened livestock as well. The Natural 
History Survey report describes one of these episodes as follows: 

The sheep. ..were driven into a small, untreated bluegrass pasture across a gravel road from a field which 
had been treated with dieldrin spray on May 6. Evidently some spray had drifted across the road into the pasture, 
for the sheep began to show symptoms of intoxication almost at once. ..They lost interest in food and displayed 
extreme restlessness, following the pasture fence around and around apparently searching for a way out. .They 
refused to be driven, bleated almost continuously, and stood with their heads lowered; they were finally carried 
from the pasture.. They displayed great desire for water. Two of the sheep were found dead in the stream passing 
through the pasture, and the remaining sheep were repeatedly driven out of the stream, several having to be 
dragged forcibly from the water. Three of the sheep eventually died; those remaining recovered to all outward 

This, then, was the picture at the end of 1955. Although the chemical war went on in 
succeeding years, the trickle of research funds dried up completely. Requests for money for 
wildlife-insecticide research were included in annual budgets submitted to the Illinois 
legislature by the Natural History Survey, but were invariably among the first items to be 
eliminated. It was not until 1960 that money was somehow found to pay the expenses of one 
field assistant— to do work that could easily have occupied the time of four men. 
The desolate picture of wildlife loss had changed little when the biologists resumed the studies 
broken off in 1955. In the meantime, the chemical had been changed to the even more toxic 
aldrin, 100 to 300 times as toxic as DDT in tests on quail. By 1960, every species of wild mammal 
known to inhabit the area had suffered losses. It was even worse with the birds. In the small 
town of Donovan the robins had been wiped out, as had the grackles, starlings, and brown 

thrashers. These and many other birds were sharply reduced elsewhere. Pheasant hunters felt 
the effects of the beetle campaign sharply. The number of broods produced on treated lands 
fell off by some 50 per cent, and the number of young in a brood declined. Pheasant hunting, 
which had been good in these areas in former years, was virtually abandoned as unrewarding. 
In spite of the enormous havoc that had been wrought in the name of eradicating the Japanese 
beetle, the treatment of more than 100,000 acres in Iroquois County over an eight-year period 
seems to have resulted in only temporary suppression of the insect, which continues its 
westward movement. The full extent of the toll that has been taken by this largely ineffective 
program may never be known, for the results measured by the Illinois biologists are a minimum 
figure. If the research program had been adequately financed to permit full coverage, the 
destruction revealed would have been even more appalling. But in the eight years of the 
program, only about $6000 was provided for biological field studies. Meanwhile the federal 
government had spent about $375,000 for control work and additional thousands had been 
provided by the state. The amount spent for research was therefore a small fraction of 1 per 
cent of the outlay for the chemical program. 

These midwestern programs have been conducted in a spirit of crisis, as though the advance of 
the beetle presented an extreme peril justifying any means to combat it. This of course is a 
distortion of the facts, and if the communities that have endured these chemical drenchings 
had been familiar with the earlier history of the Japanese beetle in the United States they 
would surely have been less acquiescent. The eastern states, which had the good fortune to 
sustain their beetle invasion in the days before the synthetic insecticides had been invented, 
have not only survived the invasion but have brought the insect under control by means that 
represented no threat whatever to other forms of life. There has been nothing comparable to 
the Detroit or Sheldon sprayings in the East. The effective methods there involved the bringing 
into play of natural forces of control which have the multiple advantages of permanence and 
environmental safety. During the first dozen years after its entry into the United States, the 
beetle increased rapidly, free of the restraints that in its native land hold it in check. But by 
1945 it had become a pest of only minor importance throughout much of the territory over 
which it had spread. Its decline was largely a consequence of the importation of parasitic 
insects from the Fa r East and of the establishment of disease organisms fatal to it. 
Between 1920 and 1933, as a result of diligent searching throughout the native range of the 
beetle, some 34 species of predatory or parasitic insects had been imported from the Orient in 
an effort to establish natural control. Of these, five became well established in the eastern 
United States. The most effective and widely distributed is a parasitic wasp from Korea and 
China, Tiphia vernalis. The female Tiphia, finding a beetle grub in the soil, injects a paralyzing 
fluid and attaches a single egg to the undersurface of the grub. The young wasp, hatching as a 
larva, feeds on the paralyzed grub and destroys it. In some 25 years, colonies of Tiphia were 
introduced into 14 eastern states in a cooperative program of state and federal agencies. The 
wasp became widely established in this area and is generally credited by entomologists with an 
important role in bringing the beetle under control. An even more important role has been 
played by a bacterial disease that affects beetles of the family to which the Japanese beetle 
belongs— the scarabaeids. It is a highly specific organism, attacking no other type of insects, 
harmless to earthworms, warm-blooded animals, and plants. The spores of the disease occur in 

soil. When ingested by a foraging beetle grub they multiply prodigiously in its blood, causing it 
to turn an abnormally white color, hence the popular name, 'milky disease'. 
Milky disease was discovered in New Jersey in 1933. By 1938 it was rather widely prevalent in 
the older areas of Japanese beetle infestation. In 1939 a control program was launched, 
directed at speeding up the spread of the disease. No method had been developed for growing 
the disease organism in an artificial medium, but a satisfactory substitute was evolved; infected 
grubs are ground up, dried, and combined with chalk. In the standard mixture a gram of dust 
contains 100 million spores. Between 1939 and 1953 some 94,000 acres in 14 eastern states 
were treated in a cooperative federal state program; otherareas on federal lands were treated; 
and an unknown but extensive area was treated by private organizations or individuals. By 
1945, milky spore disease was raging among the beetle populations of Connecticut, New York, 
New Jersey, Delaware, and Maryland. In some test areas infection of grubs had reached as high 
as 94 per cent. The distribution program was discontinued as a governmental enterprise in 
1953 and production was taken over by a private laboratory, which continues to supply 
individuals, garden clubs, citizens' associations, and all others interested in beetle control. 
The eastern areas where this program was carried out now enjoy a high degree of natural 
protection from the beetle. The organism remains viable in the soil for years and therefore 
becomes to all intents and purposes permanently established, increasing in effectiveness, and 
being continuously spread by natural agencies. Why, then, with this impressive record in the 
East, were the same procedures not tried in Illinois and the other mid- western states where the 
chemical battle of the beetles is now being waged with such fury? 

We are told that inoculation with milky spore disease is 'too expensive'— although no one 
found it so in the 14 eastern states in the 1940s. And by what sort of accounting was the 'too 
expensive' judgment reached? Certainly not by any that assessed the true costs of the total 
destruction wrought by such programs as the Sheldon spraying. This judgment also ignores the 
fact that inoculation with the spores need be done only once; the first cost is the only cost. We 
are told also that milky spore disease cannot be used on the periphery of the beetle's range 
because it can be established only where a large grub population is already present in the soil. 
Like many other statements in support of spraying, this one needs to be questioned. The 
bacterium that causes milky spore disease has been found to infect at least 40 other species of 
beetles which collectively have quite a wide distribution and would in all probability serve to 
establish the disease even where the Japanese beetle population is very small or nonexistent. 
Furthermore, because of the long viability of the spores in soil they can be introduced even in 
the complete absence of grubs, as on the fringe of the present beetle infestation, there to await 
the advancing population. 

Those who want immediate results, at whatever cost, will doubtless continue to use chemicals 
against the beetle. So will those who favor the modern trend to built-in obsolescence, for 
chemical control is self-perpetuating, needing frequent and costly repetition. On the other 
hand, those who are willing to wait an extra season or two for full results will turn to milky 
disease; they will be rewarded with lasting control that becomes more, rather than less 
effective with the passage of time. 

An extensive program of research is under way in the United States Department of Agriculture 
laboratory at Peoria, Illinois, to find a way to culture the organism of milky disease on an 
artificial medium. This will greatly reduce its cost and should encourage its more extensive use. 

After years of work, some success has now been reported. When this 'breakthrough' is 
thoroughly established perhaps some sanity and perspective will be restored to our dealings 
with the Japanese beetle, which at the peak of its depredations never justified the nightmare 
excesses of some of these Midwestern programs. . . . 

Incidents like the eastern Illinois spraying raise a question that is not only scientific but moral. 
The question is whether any civilization can wage relentless war on life without destroying 
itself, and without losing the right to be called civilized. These insecticides are not selective 
poisons; they do not single out the one species of which we desire to be rid. Each of them is 
used for the simple reason that it is a deadly poison. It therefore poisons all life with which it 
comes in contact: the cat beloved of some family, the farmer's cattle, the rabbit in the field, and 
the horned lark out of the sky. These creatures are innocent of any harm to man. Indeed, by 
their very existence they and their fellows make his life more pleasant. Yet he rewards them 
with a death that is not only sudden but horrible. Scientific observers at Sheldon described the 
symptoms of a meadowlark found near death: 'Although it lacked muscular coordination and 
could not fly or stand, it continued to beat its wings and clutch with its toes while lying on its 
side. Its beak was held open and breathing was labored.' Even more pitiful was the mute 
testimony of the dead ground squirrels, which 'exhibited a characteristic attitude in death. The 
back was bowed, and the forelegs with the toes of the feet tightly clenched were drawn close 
to the thorax. ..The head and neck were outstretched and the mouth often contained dirt, 
suggesting that the dying animal had been biting at the ground.' 

By acquiescing in an act that can cause such suffering to a living creature, who among us is not 
diminished as a human being? 

8. And No Birds Sing 

OVER INCREASINGLY large areas of the United States, spring now comes unheralded by 
the return of the birds, and the early mornings are strangely silent where once they were filled 
with the beauty of bird song. This sudden silencing of the song of birds, this obliteration of the 
color and beauty and interest they lend to our world have come about swiftly, insidiously, and 
unnoticed by those whose communities are as yet unaffected. From the town of Hinsdale, 
Illinois, a housewife wrote in despair to one of the world's leading ornithologists, Robert 
Cushman Murphy, Curator Emeritus of Birds at the American Museum of Natural History. 
Here in our village the elm trees have been sprayed for several years [she wrote in 1958]. When 
we moved here six years ago, there was a wealth of bird life; I put up a feeder and had a steady 
stream of cardinals, chickadees, downies and nuthatches all winter, and the cardinals and 
chickadees brought their young ones in the summer. After several years of DDT spray, the town 
is almost devoid of robins and starlings; chickadees have not been on my shelf for two years, 
and this year the cardinals are gone too; the nesting population in the neighborhood seems to 
consist of one dove pair and perhaps one catbird family. 

It is hard to explain to the children that the birds have been killed off, when they have learned 
in school that a Federal law protects the birds from killing or capture. 'Will they ever come 
back?' they ask, and I do not have the answer. The elms are still dying, and so are the birds. Is 
anything being done? Can anything be done? Can / do anything? A year after the federal 
government had launched a massive spraying program against the fire ant, an Alabama woman 
wrote: 'Our place has been a veritable bird sanctuary for over half a century. Last July we all 
remarked, "There are more birds than ever." Then, suddenly, in the second week of August, 
they all disappeared. I was accustomed to rising early to care for my favorite mare that had a 
young filly. There was not a sound of the song of a bird. It was eerie, terrifying. What was man 
doing to our perfect and beautiful world? Finally, five months later a blue jay appeared and a 
wren.' The autumn months to which she referred brought other somber reports from the deep 
South, where in Mississippi, Louisiana, and Alabama the Field Notes published quarterly by the 
National Audubon Society and the United States Fish and Wildlife Service noted the striking 
phenomenon of 'blank spots weirdly empty of virtually all bird life'. The Field Notes are a 
compilation of the reports of seasoned observers who have spent many years afield in their 
particular areas and have unparalleled knowledge of the normal bird life of the region. One 
such observer reported that in driving about southern Mississippi that fall she saw 'no land 
birds at all for long distances'. Another in Baton Rouge reported that the contents of her 
feeders had lain untouched 'for weeks on end', while fruiting shrubs in her yard, that ordinarily 
would be stripped clean by that time, still were laden with berries. Still another reported that 
his picture window, 'which often used to frame a scene splashed with the red of 40 or 50 
cardinals and crowded with other species, seldom permitted a view of as many as a bird or two 
at a time.' Professor Maurice Brooks of the University of West Virginia, an authority on the 
birds of the Appalachian region, reported that the West Virginia bird population had undergone 
'an incredible reduction'. One story might serve as the tragic symbol of the fate of the birds— a 
fate that has already overtaken some species, and that threatens all. It is the story of the robin, 

the bird known to everyone. To millions of Americans, the season's first robin means that the 
grip of winter is broken. Its coming is an event reported in newspapers and told eagerly at the 
breakfast table. And as the number of migrants grows and the first mists of green appear in the 
woodlands, thousands of people listen for the first dawn chorus of the robins throbbing in the 
early morning light. But now all is changed, and not even the return of the birds may be taken 
for granted. The survival of the robin, and indeed of many other species as well, seems fatefully 
linked with the American elm, a tree that is part of the history of thousands of towns from the 
Atlantic to the Rockies, gracing their streets and their village squares and college campuses with 
majestic archways of green. Now the elms are stricken with a disease that afflicts them 
throughout their range, a disease so serious that many experts believe all efforts to save the 
elms will in the end be futile. It would be tragic to lose the elms, but it would be doubly tragic if, 
in vain efforts to save them, we plunge vast segments of our bird populations into the night of 
extinction. Yet this is precisely what is threatened. The so-called Dutch elm disease entered the 
United States from Europe about 1930 in elm burl logs imported for the veneer industry. It is a 
fungus disease; the organism invades the water-conducting vessels of the tree, spreads by 
spores carried by the flow of sap, and by its poisonous secretions as well as by mechanical 
clogging causes the branches to wilt and the tree to die. The disease is spread from diseased to 
healthy trees by elm bark beetles. The galleries which the insects have tunneled out under the 
bark of dead trees become contaminated with spores of the invading fungus, and the spores 
adhere to the insect body and are carried wherever the beetle flies. Efforts to control the 
fungus disease of the elms have been directed largely toward control of the carrier insect. In 
community after community, especially throughout the strongholds of the American elm, the 
Midwest and New England, intensive spraying has become a routine procedure. 
What this spraying could mean to bird life, and especially to the robin, was first made clear by 
the work of two ornithologists at Michigan State University, Professor George Wallace and one 
of his graduate students, John Mehner. When Mr. Mehner began work for the doctorate in 
1954, he chose a research project that had to do with robin populations. This was quite by 
chance, for at that time no one suspected that the robins were in danger. But even as he 
undertook the work, events occurred that were to change its character and indeed to deprive 
him of his material. Spraying for Dutch elm disease began in a small way on the university 
campus in 1954. The following year the city of East Lansing (where the university is located) 
joined in, spraying on the campus was expanded, and, with local programs for gypsy moth and 
mosquito control also under way, the rain of chemicals increased to a downpour. During 1954, 
the year of the first light spraying, all seemed well. The following spring the migrating robins 
began to return to the campus as usual. Like the bluebells in Tomlinson's haunting essay 'The 
Lost Wood', they were 'expecting no evil' as they reoccupied their familiar territories. But soon 
it became evident that something was wrong. Dead and dying robins began to appear in the 
campus. Few birds were seen in their normal foraging activities or assembling in their usual 
roosts. Few nests were built; few young appeared. The pattern was repeated with monotonous 
regularity in succeeding springs. The sprayed area had become a lethal trap in which each wave 
of migrating robins would be eliminated in about a week. Then new arrivals would come in, 
only to add to the numbers of doomed birds seen on the campus in the agonized tremors that 
precede death. 'The campus is serving as a graveyard for most of the robins that attempt to 
take up residence in the spring,' said Dr. Wallace. But why? At first he suspected some disease 

of the nervous system, but soon it became evident that 'in spite of the assurances of the 
insecticide people that their sprays were "harmless to birds" the robins were really dying of 
insecticidal poisoning; they exhibited the well-known symptoms of loss of balance, followed by 
tremors, convulsions, and death.' 

Several facts suggested that the robins were being poisoned, not so much by direct contact 
with the insecticides as indirectly, by eating earthworms. Campus earthworms had been fed 
inadvertently to crayfish in a research project and all the crayfish had promptly died. A snake 
kept in a laboratory cage had gone into violent tremors after being fed such worms. And 
earthworms are the principal food of robins in the spring. A key piece in the jigsaw puzzle of the 
doomed robins was soon to be supplied by Dr. Roy Barker of the Illinois Natural History Survey 
at Urbana. Dr. Barker's work, published in 1958, traced the intricate cycle of events by which 
the robins' fate is linked to the elm trees by way of the earthworms. The trees are sprayed in 
the spring (usually at the rate of 2 to 5 pounds of DDT per 50-foot tree, which may be the 
equivalent of as much as 23 pounds per acre where elms are numerous) and often again in July, 
at about half this concentration. Powerful sprayers direct a stream of poison to all parts of the 
tallest trees, killing directly not only the target organism, the bark beetle, but other insects, 
including pollinating species and predatory spiders and beetles. The poison forms a tenacious 
film over the leaves and bark. Rains do not wash it away. In the autumn the leaves fall to the 
ground, accumulate in sodden layers, and begin the slow process of becoming one with the soil. 
In this they are aided by the toil of the earthworms, who feed in the leaf litter, for elm leaves 
are among their favorite foods. In feeding on the leaves the worms also swallow the insecticide, 
accumulating and concentrating it in their bodies. Dr. Barker found deposits of DDT throughout 
the digestive tracts of the worms, their blood vessels, nerves, and body wall. Undoubtedly 
some of the earthworms themselves succumb, but others survive to become 'biological 
magnifiers' of the poison. In the spring the robins return to provide another link in the cycle. As 
few as 11 large earthworms can transfer a lethal dose of DDT to a robin. And 11 worms form a 
small part of a day's rations to a bird that eats 10 to 12 earthworms in as many minutes. 
Not all robins receive a lethal dose, but another consequence may lead to the extinction of 
their kind as surely as fatal poisoning. The shadow of sterility lies over all the bird studies and 
indeed lengthens to include all living things within its potential range. There are now only two 
or three dozen robins to be found each spring on the entire 185-acre campus of Michigan State 
University, compared with a conservatively estimated 370 adults in this area before spraying. In 
1954 every robin nest under observation by Mehner produced young. Toward the end of June, 
1957, when at least 370 young birds (the normal replacement of the adult population) would 
have been foraging over the campus in the years before spraying began, Mehner could find only 
one young robin. A year later Dr. Wallace was to report: 'At no time during the spring or 
summer [of 1958] did I see a fledgling robin anywhere on the main campus, and so far I have 
failed to find anyone else who has seen one there.' 

Part of this failure to produce young is due, of course, to the fact that one or more of a pair of 
robins dies before the nesting cycle is completed. But Wallace has significant records which 
point to something more sinister— the actual destruction of the birds' capacity to reproduce. 
He has, for example, 'records of robins and other birds building nests but laying no eggs, and 
others laying eggs and incubating them but not hatching them. We have one record of a robin 
that sat on its eggs faithfully for 21 days and they did not hatch. The normal incubation period 

is 13 days. ..Our analyses are showing high concentrations of DDT in the testes and ovaries of 
breeding birds,' he told a congressional committee in 1960. 'Ten males had amounts ranging 
from 30 to 109 parts per million in the testes, and two females had 151 and 211 parts per 
million respectively in the egg follicles in their ovaries.' Soon studies in other areas began to 
develop findings equally dismal. Professor Joseph Hickey and his students at the University of 
Wisconsin, after careful comparative studies of sprayed and unsprayed areas, reported the 
robin mortality to be at least 86 to 88 per cent. The Cranbrook Institute of Science at Bloomfield 
Hills, Michigan, in an effort to assess the extent of bird loss caused by the spraying of the elms, 
asked in 1956 that all birds thought to be victims of DDT poisoning be turned in to the institute 
for examination. The request had a response beyond all expectations. Within a few weeks the 
deep-freeze facilities of the institute were taxed to capacity, so that other specimens had to be 
refused. By 1959 a thousand poisoned birds from this single community had been turned in or 
reported. Although the robin was the chief victim (one woman calling the institute reported 12 
robins lying dead on her lawn as she spoke), 63 different species were included among the 
specimens examined at the institute. The robins, then, are only one part of the chain of 
devastation linked to the spraying of the elms, even as the elm program is only one of the 
multitudinous spray programs that cover our land with poisons. Heavy mortality has occurred 
among about 90 species of birds, including those most familiar to suburbanites and amateur 
naturalists. The populations of nesting birds in general have declined as much as 90 per cent in 
some of the sprayed towns. As we shall see, all the various types of birds are affected— ground 
feeders, treetop feeders, bark feeders, predators. It is only reasonable to suppose that all birds 
and mammals heavily dependent on earthworms or other soil organisms for food are 
threatened by the robins' fate. Some 45 species of birds include earthworms in their diet. 
Among them is the woodcock, a species that winters in southern areas recently heavily sprayed 
with heptachlor. Two significant discoveries have now been made about the woodcock. 
Production of young birds on the New Brunswick breeding grounds is definitely reduced, and 
adult birds that have been analyzed contain large residues of DDT and heptachlor. Already 
there are disturbing records of heavy mortality among more than 20 other species of ground- 
feeding birds whose food— worms, ants, grubs, or other soil organisms— has been poisoned. 
These include three of the thrushes whose songs are among the most exquisite of bird voices, 
the olive-backed, the wood, and the hermit. And the sparrows that flit through the shrubby 
understory of the woodlands and forage with rustling sounds amid the fallen leaves— the song 
sparrow and the white-throat— these, too, have been found among the victims of the elm 
sprays. Mammals, also, may easily be involved in the cycle, directly or indirectly. Earthworms 
are important among the various foods of the raccoon, and are eaten in the spring and fall by 
opossums. Such subterranean tunnelers as shrews and moles capture them in numbers, and 
then perhaps pass on the poison to predators such as screech owls and barn owls. 
Several dying screech owls were picked up in Wisconsin following heavy rains in spring, perhaps 
poisoned by feeding on earthworms. Hawks and owls have been found in convulsions— great 
horned owls, screech owls, red-shouldered hawks, sparrow hawks, marsh hawks. These may be 
cases of secondary poisoning, caused by eating birds or mice that have accumulated 
insecticides in their livers or other organs. Nor is it only the creatures that forage on the ground 
or those who prey on them that are endangered by the foliar spraying of the elms. All of the 
treetop feeders, the birds that glean their insect food from the leaves, have disappeared from 

heavily sprayed areas, among them those woodland sprites the kinglets, both ruby-crowned 
and golden-crowned, the tiny gnatcatchers, and many of the warblers, whose migrating hordes 
flow through the trees in spring in a multicolored tide of life. In 1956, a late spring delayed 
spraying so that it coincided with the arrival of an exceptionally heavy wave of warbler 
migration. Nearly all species of warblers present in the area were represented in the heavy kill 
that followed. In Whitefish Bay, Wisconsin, at least a thousand myrtle wa rblers could be seen in 
migration during formeryears; in 1958, afterthe spraying of the elms, observers could find only 
two. So, with additions from other communities, the list grows, and the warblers killed by the 
spray include those that most charm and fascinate all who are aware of them: the black-and- 
white, the yellow, the magnolia, and the Cape May; the ovenbird, whose call throbs in the 
Maytime woods; the Blackburnian, whose wings are touched with flame; the chestnut-sided, 
the Canadian, and the black-throated green. These treetop feeders are affected either directly 
by eating poisoned insects or indirectly by a shortage of food. 

The loss of food has also struck hard at the swallows that cruise the skies, straining out the 
aerial insects as herring strain the plankton of the sea. A Wisconsin naturalist reported: 
'Swallows have been hard hit. Everyone complains of how few they have compared to four or 
five years ago. Our sky overhead was full of them only four years ago. Now we seldom see 
any.. .This could be both lack of insects because of spray, or poisoned insects.' Of other birds 
this same observer wrote: 'Another striking loss is the phoebe. Flycatchers are scarce 
everywhere but the early hardy common phoebe is no more. I've seen one this spring and only 
one last spring. Other birders in Wisconsin make the same complaint. I have had five or six pair 
of cardinals in the past, none now. Wrens, robins, catbirds and screech owls have nested each 
year in our garden. There are none now. Summer mornings are without bird song. Only pest 
birds, pigeons, starlings and English sparrows remain. It is tragic and I can't bear it.' 
The dormant sprays applied to the elms in the fall, sending the poison into every little crevice in 
the bark, are probably responsible for the severe reduction observed in the number of 
chickadees, nuthatches, titmice, woodpeckers, and brown creepers. During the winter of 1957- 
58, Dr. Wallace saw no chickadees or nuthatches at his home feeding station for the first time 
in many years. Three nuthatches he found later provided a sorry little step-by-step lesson in 
cause and effect: one was feeding on an elm, another was found dying of typical DDT 
symptoms, the third was dead. The dying nuthatch was later found to have 226 parts per 
million of DDT in its tissues. The feeding habits of all these birds not only make them especially 
vulnerable to insect sprays but also make their loss a deplorable one for economic as well as 
less tangible reasons. The summer food of the white-breasted nuthatch and the brown creeper, 
for example, includes the eggs, larvae, and adults of a very large number of insects injurious to 
trees. About three quarters of the food of the chickadee is animal, including all stages of the life 
cycle of many insects. The chickadee's method of feeding is described in Bent's monumental 
Life Histories of North American birds: 'As the flock moves along each bird examines minutely 
bark, twigs, and branches, searching for tiny bits of food (spiders' eggs, cocoons, or other 
dormant insect life).' Various scientific studies have established the critical role of birds in insect 
control in various situations. Thus, woodpeckers are the primary control of the Engelmann 
spruce beetle, reducing its populations from 45 to 98 per cent and are important in the control 
of the codling moth in apple orchards. Chickadees and other winter-resident birds can protect 
orchards against the cankerworm. 

But what happens in nature is not allowed to happen in the modem, chemical-drenched world, 
where spraying destroys not only the insects but their principal enemy, the birds. When later 
there is a resurgence of the insect population, as almost always happens, the birds are not 
there to keep their numbers in check. As the Curator of Birds at the Milwaukee Public Museum, 
Owen J. Gromme, wrote to the Milwaukee Journal: 'The greatest enemy of insect life is other 
predatory insects, birds, and some small mammals, but DDT kills indiscriminately, including 
nature's own safeguards or policemen... In the name of progress are we to become victims of 
our own diabolical means of insect control to provide temporary comfort, only to lose out to 
destroying insects later on? By what means will we control new pests, which will attack 
remaining tree species after the elms are gone, when nature's safeguards (the birds) have been 
wiped out by poison?' 

Mr. Gromme reported that calls and letters about dead and dying birds had been increasing 
steadily during the years since spraying began in Wisconsin. Questioning always revealed that 
spraying or fogging had been done in the area where the birds were dying. 
Mr. Gramme's experience has been shared by ornithologists and conservationists at most of 
the research centers of the Midwest such as the Cranbrook Institute in Michigan, the Illinois 
Natural History Survey, and the University of Wisconsin. A glance at the Letters -from-Readers 
column of newspapers almost anywhere that spraying is being done makes clear the fact that 
citizens are not only becoming aroused and indignant but that often they show a keener 
understanding of the dangers and inconsistencies of spraying than do the officials who order it 
done. 'I am dreading the days to come soon now when many beautiful birds will be dying in our 
back yard,' wrote a Milwaukee woman. 'This is a pitiful, heartbreaking experience... It is, 
moreover, frustrating and exasperating, for it evidently does not serve the purpose this 
slaughter was intended to serve... Taking a long look, can you save trees without also saving 
birds? Do they not, in the economy of nature, save each other? Isn't it possible to help the 
balance of nature without destroying it?' The idea that the elms, majestic shade trees though 
they are, are not 'sacred cows' and do not justify an 'open end' campaign of destruction against 
all other forms of life is expressed in other letters. 'I have always loved our elm trees which 
seemed like trademarks on our landscape,' wrote another Wisconsin woman. 'But there are 
many kinds of trees. ..We must save our birds, too. Can anyone imagine anything so cheerless 
and dreary as a springtime without a robin's song?' To the public the choice may easily appear 
to be one of stark black-or-white simplicity: Shall we have birds or shall we have elms? But it is 
not as simple as that, and by one of the ironies that abound throughout the field of chemical 
control we may very well end by having neither if we continue on our present, well-traveled 
road. Spraying is killing the birds but it is not saving the elms. The illusion that salvation of the 
elms lies at the end of a spray nozzle is a dangerous will-o'- the-wisp that is leading one 
community after another into a morass of heavy expenditures, without producing lasting 
results. Greenwich, Connecticut sprayed regularly for ten years. Then a drought year brought 
conditions especially favorable to the beetle and the mortality of elms went up 1000 per cent. 
In Urbana, Illinois, where the University of Illinois is located, Dutch elm disease first appeared in 
1951. Spraying was undertaken in 1953. By 1959, in spite of six years' spraying, the university 
campus had lost 86 per cent of its elms, half of them victims of Dutch elm disease. In Toledo, 
Ohio, a similar experience caused the Superintendent of Forestry, Joseph A. Sweeney, to take a 
realistic look at the results of spraying. Spraying was begun there in 1953 and continued 

through 1959. Meanwhile, however, Mr. Sweeney had noticed that a city-wide infestation of 
the cottony maple scale was worse after the spraying recommended by 'the books and the 
authorities' than it had been before. He decided to review the results of spraying for Dutch elm 
disease for himself. His findings shocked him. In the city of Toledo, he found, 'the only areas 
under any control were the areas where we used some promptness in removing the diseased or 
brood trees. Where we depended on spraying the disease was out of control. In the country 
where nothing has been done the disease has not spread as fast as it has in the city. This 
indicates that spraying destroys any natural enemies. 'We are abandoning spraying for the 
Dutch elm disease. This has brought me into conflict with the people who back any 
recommendations by the United States Department of Agriculture but I have the facts and will 
stick with them.' It is difficult to understand why these midwestern towns, to which the elm 
disease spread only rather recently, have so unquestioningly embarked on ambitious and 
expensive spraying programs, apparently without waiting to inquire into the experience of 
other areas that have had longer acquaintance with the problem. New York State, for example, 
has certainly had the longest history of continuous experience with Dutch elm disease, for it 
was via the Port of New York that diseased elm wood is thought to have entered the United 
States about 1930. And New York State today has a most impressive record of containing and 
suppressing the disease. Yet it has not relied upon spraying. In fact, its agricultural extension 
service does not recommend spraying as a community method of control. 
How, then, has New York achieved its fine record? From the early years of the battle for the 
elms to the present time, it has relied upon rigorous sanitation, or the prompt removal and 
destruction of all diseased or infected wood. In the beginning some of the results were 
disappointing, but this was because it was not at first understood that not only diseased trees 
but all elm wood in which the beetles might breed must be destroyed. Infected elm wood, after 
being cut and stored for firewood, will release a crop of fungus -carrying beetles unless burned 
before spring. It is the adult beetles, emerging from hibernation to feed in late April and May, 
that transmit Dutch elm disease. New York entomologists have learned by experience what 
kinds of beetle-breeding material have real importance in the spread of the disease. By 
concentrating on this dangerous material, it has been possible not only to get good results, but 
to keep the cost of the sanitation program within reasonable limits. By 1950 the incidence of 
Dutch elm disease in New York City had been reduced to of 1 per cent of the city's 55,000 elms. 
A sanitation program was launched in Westchester County in 1942. 

During the next 14 years the average annual loss of elms was only of 1 per cent a year. Buffalo, 
with 185,000 elms, has an excellent record of containing the disease by sanitation, with recent 
annual losses amounting to only of 1 per cent. In other words, at this rate of loss it would take 
about 300 years to eliminate Buffalo's elms. What has happened in Syracuse is especially 
impressive. There no effective program was in operation before 1957. Between 1951 and 1956 
Syracuse lost nearly 3000 elms. Then, under the direction of Howa rd C. Miller of the New York 
State University College of Forestry, an intensive drive was made to remove all diseased elm 
trees and all possible sources of beetle-breeding elm wood. The rate of loss is now well below 1 
per cent a year. The economy of the sanitation method is stressed by New York experts in 
Dutch elm disease control. 'In most cases the actual expense is small compared with the 
probable saving,' says J. G. Matthysse of the New York State College of Agriculture. 'If it is a 
case of a dead or broken limb, the limb would have to be removed eventually, as a precaution 

against possible property damage or personal injury. If it is a fuel-wood pile, the wood can be 
used before spring, the bark can be peeled from the wood, or the wood can be stored in a dry 
place. In the case of dying or dead elm trees, the expense of prompt removal to prevent Dutch 
elm disease spread is usually no greater than would be necessary later, for most dead trees in 
urban regions must be removed eventually.' The situation with regard to Dutch elm disease is 
therefore not entirely hopeless provided informed and intelligent measures are taken. While it 
cannot be eradicated by any means now known, once it has become established in a 
community, it can be suppressed and contained within reasonable bounds by sanitation, and 
without the use of methods that are not only futile but involve tragic destruction of bird life. 
Other possibilities lie within the field of forest genetics, where experiments offer hope of 
developing a hybrid elm resistant to Dutch elm disease. The European elm is highly resistant, 
and many of them have been planted in Washington, D.C. Even during a period when a high 
percentage of the city's elms were affected, no cases of Dutch elm disease were found among 
these trees. Replanting through an immediate tree nursery and forestry program is being urged 
in communities that are losing large numbers of elms. This is important, and although such 
programs might well include the resistant European elms, they should aim at a variety of 
species so that no future epidemic could deprive a community of its trees. The key to a healthy 
plant or animal community lies in what the British ecologist Charles Elton calls 'the conservation 
of variety'. What is happening now is in large part a result of the biological unsophistication of 
past generations. Even a generation ago no one knew that to fill large areas with a single 
species of tree was to invite disaster. And so whole towns lined their streets and dotted their 
parks with elms, and today the elms die and so do the birds. . . . 

Like the robin, another American bird seems to be on the verge of extinction. This is the 
national symbol, the eagle. Its populations have dwindled alarmingly within the past decade. 
The facts suggest that something is at work in the eagle's environment which has virtually 
destroyed its ability to reproduce. What this may be is not yet definitely known, but there is 
some evidence that insecticides are responsible. 

The most intensively studied eagles in North America have been those nesting along a stretch 
of coast from Tampa to Fort Myers on the western coast of Florida. There a retired banker from 
Winnipeg, Charles Broley, achieved ornithological fame by banding more than 1,000 young bald 
eagles during the years 1939-49. (Only 166 eagles had been banded in all the earlier history of 
birdbanding.) Mr. Broley banded eagles as young birds during the winter months before they 
had left their nests. Later recoveries of banded birds showed that these Florida-born eagles 
range northward along the coast into Canada as far as Prince Edward Island, although they had 
previously been considered nonmigratory. In the fall they return to the South, their migration 
being observed at such famous vantage points as Hawk Mountain in eastern Pennsylvania. 
During the early years of his banding, Mr. Broley used to find 125 active nests a year on the 
stretch of coast he had chosen for his work. The number of young banded each year was about 
150. In 1947 the production of young birds began to decline. Some nests contained no eggs; 
others contained eggs that failed to hatch. Between 1952 and 1957, about 80 per cent of the 
nests failed to produce young. In the last year of this period only 43 nests were occupied. Seven 
of them produced young (8 eaglets); 23 contained eggs that failed to hatch; 13 were used 
merely as feeding stations by adult eagles and contained no eggs. In 1958 Mr. Broley ranged 
over 100 miles of coast before finding and banding one eaglet. Adult eagles, which had been 

seen at 43 nests in 1957, were so scarce that he observed them at only 10 nests. Although Mr. 
Broley's death in 1959 terminated this valuable series of uninterrupted observations, reports by 
the Florida Audubon Society, as well as from New Jersey and Pennsylvania, confirm the trend 
that may well make it necessary for us to find a new national emblem. The reports of Maurice 
Broun, curator of the Hawk Mountain Sanctuary, are especially significant. Hawk Mountain is a 
picturesque mountaintop in southeastern Pennsylvania, where the easternmost ridges of the 
Appalachians form a last barrier to the westerly winds before dropping away toward the coastal 
plain. Winds striking the mountains are deflected upward so that on many autumn days there is 
a continuous updraft on which the broad-winged hawks and eagles ride without effort, covering 
many miles of their southward migration in a day. At Hawk Mountain the ridges converge and 
so do the aerial highways. The result is that from a widespread territory to the north birds pass 
through this traffic bottleneck. In his more than a score of years as custodian of the sanctuary 
there, Maurice Broun has observed and actually tabulated more hawks and eagles than any 
other American. The peak of the bald eagle migration comes in late August and early 
September. These are assumed to be Florida birds, returning to home territory after a summer 
in the North. (Later in the fall and early winter a few larger eagles drift through. These are 
thought to belong to a northern race, bound for an unknown wintering ground.) During the first 
years after the sanctuary was established, from 1935 to 1939, 40 per cent of the eagles 
observed were yearlings, easily identified by their uniformly dark plumage. But in recent years 
these immature birds have become a rarity. Between 1955 and 1959, they made up only 20 per 
cent of the total count, and in one year (1957) there was only one young eagle for every 32 
adults. Observations at Hawk Mountain are in line with findings elsewhere. One such report 
comes from Elton Fawks, an official of the Natural Resources Council of Illinois. Eagles — 
probably northern nesters— winter along the Mississippi and Illinois Rivers. In 1958 Mr. Fawks 
reported that a recent count of 59 eagles had included only one immature bird. Similar 
indications of the dying out of the race come from the world's only sanctuary for eagles alone, 
Mount Johnson Island in the Susquehanna River. The island, although only 8 miles above 
Conowingo Dam and about half a mile out from the Lancaster County shore, retains its 
primitive wildness. Since 1934 its single eagle nest has been under observation by Professor 
Herbert H. Beck, an ornithologist of Lancaster and custodian of the sanctuary. Between 1935 
and 1947 use of the nest was regular and uniformly successful. Since 1947, although the adults 
have occupied the nest and there is evidence of egg laying, no young eagles have been 
produced. On Mount Johnson Island as well as in Florida, then, the same situation prevails— 
there is some occupancy of nests by adults, some production of eggs, but few or no young 
birds. In seeking an explanation, only one appears to fit all the facts. This is that the 
reproductive capacity of the birds has been so lowered by some environmental agent that 
there are now almost no annual additions of young to maintain the race. 
Exactly this sort of situation has been produced artificially in other birds by various 
experimenters, notably Dr. James DeWitt of the United States Fish and Wildlife Service. Dr. 
DeWitt's now classic experiments on the effect of a series of insecticides on quail and 
pheasants have established the fact that exposure to DDT or related chemicals, even when 
doing no observable harm to the parent birds, may seriously affect reproduction. The way the 
effect is exerted may vary, but the end result is always the same. For example, quail into whose 
diet DDT was introduced throughout the breeding season survived and even produced normal 

numbers of fertile eggs. But few of the eggs hatched. 'Many embryos appeared to develop 
normally during the early stages of incubation, but died during the hatching period/ Dr. DeWitt 
said. Of those that did hatch, more than half died within 5 days. In other tests in which both 
pheasants and quail were the subjects, the adults produced no eggs whatever if they had been 
fed insecticide-contaminated diets throughout the year. And at the University of California, Dr. 
Robert Rudd and Dr. Richard Genelly reported similar findings. When pheasants received 
dieldrin in their diets, 'egg production was markedly lowered and chick survival was poor.' 
According to these authors, the delayed but lethal effect on the young birds follows from 
storage of dieldrin in the yolk of the egg, from which it is gradually assimilated during 
incubation and after hatching. This suggestion is strongly supported by recent studies by Dr. 
Wallace and a graduate student, Richard F. Bernard, who found high concentrations of DDT in 
robins on the Michigan State University campus. They found the poison in all of the testes of 
male robins examined, in developing egg follicles, in the ovaries of females, in completed but 
unlaid eggs, in the oviducts, in unhatched eggs from deserted nests, in embryos within the eggs, 
and in a newly hatched, dead nestling. These important studies establish the fact that the 
insecticidal poison affects a generation once removed from initial contact with it. Storage of 
poison in the egg, in the yolk material that nourishes the developing embryo, is a virtual death 
warrant and explains why so many of DeWitt's birds died in the egg or a few days after 

Laboratory application of these studies to eagles presents difficulties that are nearly 
insuperable, but field studies are now under way in Florida, New Jersey, and elsewhere in the 
hope of acquiring definite evidence as to what has caused the apparent sterility of much of the 
eagle population. Meanwhile, the available circumstantial evidence points to insecticides. In 
localities where fish are abundant they make up a large part of the eagle's diet (about 65 per 
cent in Alaska; about 52 per cent in the Chesapeake Bay area). Almost unquestionably the 
eagles so long studied by Mr. Broley were predominantly fish eaters. Since 1945 this particular 
coastal area has been subjected to repeated sprayings with DDT dissolved in fuel oil. The 
principal target of the aerial spraying was the salt-marsh mosquito, which inhabits the marshes 
and coastal areas that are typical foraging areas for the eagles. Fishes and crabs were killed in 
enormous numbers. Laboratory analyses of their tissues revealed high concentrations of DDT— 
as much as 46 parts per million. Like the grebes of Clear Lake, which accumulated heavy 
concentrations of insecticide residues from eating the fish of the lake, the eagles have almost 
certainly been storing up the DDT in the tissues of their bodies. And like the grebes, the 
pheasants, the quail, and the robins, they are less and less able to produce young and to 
preserve the continuity of their race. . . . 

From all over the world come echoes of the peril that faces birds in our modern world. The 
reports differ in detail, but always repeat the theme of death to wildlife in the wake of 
pesticides. Such are the stories of hundreds of small birds and partridges dying in France after 
vine stumps were treated with an arsenic-containing herbicide, or of partridge shoots in 
Belgium, once famous for the numbers of their birds, denuded of partridges after the spraying 
of nearby farmlands. In England the major problem seems to be a specialized one, linked with 
the growing practice of treating seed with insecticides before sowing. Seed treatment is not a 
wholly new thing, but in earlier years the chemicals principally used were fungicides. No effects 
on birds seem to have been noticed. Then about 1956 there was a change to dual-purpose 

treatment; in addition to a fungicide, dieldrin, aldrin, or heptachlor was added to combat soil 
insects. Thereupon the situation changed for the worse. 

In the spring of 1960 a deluge of reports of dead birds reached British wildlife authorities, 
including the British Trust for Ornithology, the Royal Society for the Protection of Birds, and the 
Game Birds Association. 'The place is like a battlefield,' a landowner in Norfolk wrote. 'My 
keeper has found innumerable corpses, including masses of small birds— Chaffinches, 
Greenfinches, Linnets, Hedge Sparrows, also House Sparrows... the destruction of wild life is 
quite pitiful.' A gamekeeper wrote: 'My Partridges have been wiped out with the dressed corn, 
also some Pheasants and all other birds, hundreds of birds have been killed... As a lifelong 
gamekeeper it has been a distressing experience for me. It is bad to see pairs of Partridges that 
have died together.' In a joint report, the British Trust for Ornithology and the Royal Society for 
the Protection of Birds described some 67 kills of birds— a far from complete listing of the 
destruction that took place in the spring of 1960. Of these 67, 59 were caused by seed 
dressings, 8 by toxic sprays. A new wave of poisoning set in the following year. The death of 600 
birds on a single estate in Norfolk was reported to the House of Lords, and 100 pheasants died 
on a farm in North Essex. It soon became evident that more counties were involved than in 
1960 (34 compared with 23). Lincolnshire, heavily agricultural, seemed to have suffered most, 
with reports of 10,000 birds dead. But destruction involved all of agricultural England, from 
Angus in the north to Cornwall in the south, from Anglesey in the west to Norfolk in the east. 
In the spring of 1961 concern reached such a peak that a special committee of the House of 
Commons made an investigation of the matter, taking testimony from farmers, landowners, 
and representatives of the Ministry of Agriculture and of various governmental and non- 
governmental agencies concerned with wildlife. 'Pigeons are suddenly dropping out of the sky 
dead,' said one witness. 'You can drive a hundred or two hundred miles outside London and not 
see a single kestrel,' reported another. 'There has been no parallel in the present century, or at 
any time so far as I am aware, [this is] the biggest risk to wildlife and game that ever occurred in 
the country,' officials of the Nature Conservancy testified. 

Facilities for chemical analysis of the victims were most inadequate to the task, with only two 
chemists in the country able to make the tests (one the government chemist, the other in the 
employ of the Royal Society for the Protection of Birds). Witnesses described huge bonfires on 
which the bodies of the birds were burned. But efforts were made to have carcasses collected 
for examination, and of the birds analyzed, all but one contained pesticide residues. The single 
exception was a snipe, which is not a seed-eating bird. Along with the birds, foxes also may 
have been affected, probably indirectly by eating poisoned mice or birds. England, plagued by 
rabbits, sorely needs the fox as a predator. But between November 1959 and April 1960 at least 
1300 foxes died. Deaths were heaviest in the same counties from which sparrow hawks, 
kestrels, and other birds of prey virtually disappeared, suggesting that the poison was spreading 
through the food chain, reaching out from the seed eaters to the furred and feathered 
carnivores. The actions of the moribund foxes were those of animals poisoned by chlorinated 
hydrocarbon insecticides. They were seen wandering in circles, dazed and half blind, before 
dying in convulsions. 

The hearings convinced the committee that the threat to wildlife was 'most alarming'; it 
accordingly recommended to the House of Commons that 'the Minister of Agriculture and the 
Secretary of State for Scotland should secure the immediate prohibition for the use as seed 

dressings of compounds containing dieldrin, aldrin, or heptachlor, or chemicals of comparable 
toxicity.' The committee also recommended more adequate controls to ensure that chemicals 
were adequately tested under field as well as laboratory conditions before being put on the 
market. This, it is worth emphasizing, is one of the great blank spots in pesticide research 
everywhere. Manufacturers' tests on the common laboratory animals— rats, dogs, guinea 
pigs— include no wild species, no birds as a rule, no fishes, and are conducted under controlled 
and artificial conditions. Their application to wildlife in the field is anything but precise. England 
is by no means alone in its problem of protecting birds from treated seeds. Here in the United 
States the problem has been most troublesome in the rice-growing areas of California and the 
South. For a number of years California rice growers have been treating seed with DDT as 
protection against tadpole shrimp and scavenger beetles which sometimes damage seedling 
rice. California sportsmen have enjoyed excellent hunting because of the concentrations of 
waterfowl and pheasants in the rice fields. But for the past decade persistent reports of bird 
losses, especially among pheasants, ducks, and blackbirds, have come from the rice-growing 
counties. 'Pheasant sickness' became a well-known phenomenon: birds 'seek water, become 
paralyzed, and are found on the ditch banks and rice checks quivering,' according to one 
observer. The 'sickness' comes in the spring, at the time the rice fields are seeded. The 
concentration of DDT used is many times the amount that will kill an adult pheasant. 
The passage of a few years and the development of even more poisonous insecticides served to 
increase the hazard from treated seed. Aldrin, which is 100 times as toxic as DDT to pheasants, 
is now widely used as a seed coating. In the rice fields of eastern Texas, this practice has 
seriously reduced the populations of the famous tree duck, a tawny-colored, gooselike duck of 
the Gulf Coast. Indeed, there is some reason to think that the rice growers, having found a way 
to reduce the populations of blackbirds, are using the insecticide for a dual purpose, with 
disastrous effects on several bird species of the rice fields. As the habit of killing grows— the 
resort to 'eradicating' any creature that may annoy or inconvenience us— birds are more and 
more finding themselves a direct target of poisons rather than an incidental one. There is a 
growing trend toward aerial applications of such deadly poisons as parathion to 'control' 
concentrations of birds distasteful to farmers. The Fish and Wildlife Service has found it 
necessary to express serious concern over this trend, pointing out that 'parathion treated areas 
constitute a potential hazard to humans, domestic animals, and wildlife.' In southern Indiana, 
for example, a group of farmers went together in the summer of 1959 to engage a spray plane 
to treat an area of river bottomland with parathion. The area was a favored roosting site for 
thousands of blackbirds that were feeding in nearby corn fields. The problem could have been 
solved easily by a slight change in agricultural practice shift to a variety of corn with deep-set 
ears not accessible to the birds— but the farmers had been persuaded of the merits of killing by 
poison, and so they sent in the planes on their mission of death. 

The results probably gratified the farmers, for the casualty list included some 65,000 red- 
winged blackbirds and starlings. What other wildlife deaths may have gone unnoticed and 
unrecorded is not known. Parathion is not a specific for blackbirds: it is a universal killer. But 
such rabbits or raccoons or opossums as may have roamed those bottomlands and perhaps 
never visited the farmers' cornfields were doomed by a judge and jury who neither knew of 
their existence nor cared. And what of human beings? In California orchards sprayed with this 

same parathion, workers handling foliage that had been treated a month earlier collapsed and 
went into shock, and escaped death only through skilled medical attention. 
Does Indiana still raise any boys who roam through woods or fields and might even explore the 
margins of a river? If so, who guarded the poisoned area to keep out any who might wander in, 
in misguided search for unspoiled nature? Who kept vigilant watch to tell the innocent stroller 
that the fields he was about to enter were deadly— all their vegetation coated with a lethal 
film? Yet at so fearful a risk the farmers, with none to hinder them, waged their needless war 
on blackbirds. In each of these situations, one turns away to ponder the question: Who has 
made the decision that sets in motion these chains of poisonings, this ever-widening wave of 
death that spreads out, like ripples when a pebble is dropped into a still pond? Who has placed 
in one pan of the scales the leaves that might have been eaten by the beetles and in the other 
the pitiful heaps of many-hued feathers, the lifeless remains of the birds that fell before the 
unselective bludgeon of insecticidal poisons? Who has decided —who has the right to decide— 
for the countless legions of people who were not consulted that the supreme value is a world 
without insects, even though it be also a sterile world ungraced by the curving wing of a bird in 
flight? The decision is that of the authoritarian temporarily entrusted with power; he has made 
it during a moment of inattention by millions to whom beauty and the ordered world of nature 
still have a meaning that is deep and imperative. 

9. Rivers of Death 

FROM THE GREEN DEPTHS of the offshore Atlantic many paths lead back to the coast. 
They are paths followed by fish; although unseen and intangible, they are linked with the 
outflow of waters from the coastal rivers. For thousands upon thousands of years the salmon 
have known and followed these threads of fresh water that lead them back to the rivers, each 
returning to the tributary in which it spent the first months or years of life. So, in the summer 
and fall of 1953, the salmon of the river called Miramichi on the coast of New Brunswick moved 
in from their feeding grounds in the far Atlantic and ascended their native river. In the upper 
reaches of the Miramichi, in streams that gather together a network of shadowed brooks, the 
salmon deposited their eggs that autumn in beds of gravel over which the stream water flowed 
swift and cold. Such places, the watersheds of the great coniferous forests of spruce and 
balsam, of hemlock and pine, provide the kind of spawning grounds that salmon must have in 
order to survive. 

These events repeated a pattern that was age-old, a pattern that had made the Miramichi one 
of the finest salmon streams in North America. But that year the pattern was to be broken. 
During the fall and winter the salmon eggs, large and thickshelled, lay in shallow gravel-filled 
troughs, or redds, which the mother fish had dug in the stream bottom. In the cold of winter 
they developed slowly, as was their way, and only when spring at last brought thawing and 
release to the forest streams did the young hatch. At first they hid among the pebbles of the 
stream bed— tiny fish about half an inch long. They took no food, living in the large yolk sac. Not 
until it was absorbed would they begin to search the stream for small insects. 
With the newly hatched salmon in the Miramichi that spring of 1954 were young of previous 
hatchings, salmon a year or two old, young fish in brilliant coats marked with bars and bright 
red spots. These young fed voraciously, seeking out the strange and varied insect life of the 
stream. As the summer approached, all this was changed. That year the watershed of the 
Northwest Miramichi was included in a vast spraying program which the Canadian Government 
had embarked upon the previous year— a program designed to save the forests from the spruce 
budworm. The budworm is a native insect that attacks several kinds of evergreens. In eastern 
Canada it seems to become extraordinarily abundant about every 35 years. The early 1950s had 
seen such an upsurge in the budworm populations. To combat it, spraying with DDT was begun, 
first in a small way, then at a suddenly accelerated rate in 1953. Millions of acres of forests 
were sprayed instead of thousands as before, in an effort to save the balsams, which are the 
mainstay of the pulp and paper industry. 

So in 1954, in the month of June, the planes visited the forests of the Northwest Miramichi and 
white clouds of settling mist marked the crisscross pattern of their flight. The spray— one half 
pound of DDT to the acre in a solution of oil— filtered down through the balsam forests and 
some of it finally reached the ground and the flowing streams. The pilots, their thoughts only on 
their assigned task, made no effort to avoid the streams or to shut off the spray nozzles while 
flying over them; but because spray drifts so far in even the slightest stirrings of air, perhaps the 
result would have been little different if they had. 

Soon after the spraying had ended there were unmistakable signs that all was not well. Within 
wo days dead and dying fish, including many young salmon, were found along the banks of the 

stream. Brook trout also appeared among the dead fish, and along the roads and in the woods 
birds were dying. All the life of the stream was stilled. Before the spraying there had been a rich 
assortment of the water life that forms the food of salmon and trout— caddis fly larvae, living in 
loosely fitting protective cases of leaves, stems or gravel cemented together with saliva, stone 
fly nymphs clinging to rocks in the swirling currents, and the wormlike larvae of blackf lies 
edging the stones under riffles or where the stream spills over steeply slanting rocks. But now 
the stream insects were dead, killed by the DDT, and there was nothing for a young salmon to 
eat. Amid such a picture of death and destruction, the young salmon themselves could hardly 
have been expected to escape, and they did not. By August not one of the young salmon that 
had emerged from the gravel beds that spring remained. A whole year's spawning had come to 
nothing. The older young, those hatched a year or more earlier, fared only slightly better. For 
every six young of the 1953 hatch that had foraged in the stream as the planes approached, 
only one remained. Young salmon of the 1952 hatch, almost ready to go to sea, lost a third of 
their numbers. All these facts are known because the Fisheries Research Board of Canada had 
been conducting a salmon study on the Northwest Mira michi since 1950. Each year it had made 
a census of the fish living in this stream. The records of the biologists covered the number of 
adult salmon ascending to spawn, the number of young of each age group present in the 
stream, and the normal population not only of salmon but of other species of fish inhabiting the 
stream. With this complete record of prespraying conditions, it was possible to measure the 
damage done by the spraying with an accuracy that has seldom been matched elsewhere. 
The survey showed more than the loss of young fish; it revealed a serious change in the streams 
themselves. Repeated sprayings have now completely altered the stream environment, and the 
aquatic insects that are the food of salmon and trout have been killed. A great deal of time is 
required, even after a single spraying, for most of these insects to build up sufficient numbers 
to support a normal salmon population— time measured in years rather than months. The 
smaller species, such as midges and blackflies, become reestablished rather quickly. These are 
suitable food for the smallest salmon, the fry only a few months old. But there is no such rapid 
recovery of the larger aquatic insects, on which salmon in their second and third years depend. 
These are the larval stages of caddis flies, stoneflies, and mayflies. Even in the second year after 
DDT enters a stream, a foraging salmon parr would have trouble finding anything more than an 
occasional small stonefly. There would be no large stoneflies, no mayflies, no caddis flies. In an 
effort to supply this natural food, the Canadians have attempted to transplant caddis fly larvae 
and other insects to the barren reaches of the Miramichi. But of course such transplants would 
be wiped out by any repeated spraying. The budworm populations, instead of dwindling as 
expected, have proved refractory, and from 1955 to 1957 spraying was repeated in various 
parts of New Brunswick and Quebec, some places being sprayed as many as three times. By 
1957, nearly 15 million acres had been sprayed. Although spraying was then tentatively 
suspended, a sudden resurgence of budworms led to its resumption in 1960 and 1961. Indeed 
there is no evidence anywhere that chemical spraying for budworm control is more than a 
stopgap measure (aimed at saving the trees from death through defoliation over several 
successive years), and so its unfortunate side effects will continue to be felt as spraying is 
continued. In an effort to minimize the destruction of fish, the Canadian forestry officials have 
reduced the concentration of DDT from the Vi pound previously used to % pound to the acre, on 

the recommendation of the Fisheries Research Board. (In the United States the standard and 
highly lethal pound-to-the-acre still prevails.) Now, after several years in which to observe the 
effects of spraying, the Canadians find a mixed situation, but one that affords very little comfort 
to devotees of salmon fishing, provided spraying is continued. 

A very unusual combination of circumstances has so far saved the runs of the Northwest 
Miramichi from the destruction that was anticipated— a constellation of happenings that might 
not occur again in a century. It is important to understand what has happened there, and the 
reasons for it. In 1954, as we have seen, the watershed of this branch of the Miramichi was 
heavily sprayed. Thereafter, except for a narrow band sprayed in 1956, the whole upper 
watershed of this branch was excluded from the spraying program. In the fall of 1954 a tropical 
storm played its part in the fortunes of the Miramichi salmon. Hurricane Edna, a violent storm 
to the very end of its northward path, brought torrential rains to the New England and 
Canadian coasts. The resulting freshets carried streams of fresh water far out to sea and drew 
in unusual numbers of salmon. As a result, the gravel beds of the streams which the salmon 
seek out for spawning received an unusual abundance of eggs. The young salmon hatching in 
the Northwest Miramichi in the spring of 1955 found circumstances practically ideal for their 
survival. While the DDT had killed off all stream insects the year before, the smallest of the 
insects— the midges and blackf lies had returned in numbers. These are the normal food of baby 
salmon. The salmon fry of that year not only found abundant food but they had few 
competitors for it. This was because of the grim fact that the older young salmon had been 
killed off by the spraying in 1954. Accordingly, the fry of 1955 grew very fast and survived in 
exceptional numbers. They completed their stream growth rapidly and went to sea early. Many 
of them returned in 1959 to give large runs of grilse to the native stream. 
If the runs in the Northwest Miramichi are still in relatively good condition this is because 
spraying was done in one year only. The results of repeated spraying are clearly seen in other 
streams of the watershed, where alarming declines in the salmon populations are occurring. 
In all sprayed streams, young salmon of every size are scarce. The youngest are often 
'practically wiped out', the biologists report. In the main Southwest Miramichi, which was 
sprayed in 1956 and 1957, the 1959 catch was the lowest in a decade. Fishermen remarked on 
the extreme scarcity of grilse— the youngest group of returning fish. At the sampling trap in the 
estuary of the Miramichi the count of grilse was only a fourth as large in 1959 as the year 
before. In 1959 the whole Miramichi watershed produced only about 600,000 smolt (young 
salmon descending to the sea). This was less than a third of the runs of the three preceding 
years. Against such a background, the future of the salmon fisheries in New Brunswick may well 
depend on finding a substitute for drenching forests with DDT. . . . 

The eastern Canadian situation is not unique, except perhaps in the extent of forest spraying 
and the wealth of facts that have been collected. Maine, too, has its forests of spruce and 
balsam, and its problem of controlling forest insects. Maine, too, has its salmon runs— a 
remnant of the magnificent runs of former days, but a remnant hard won by the work of 
biologists and conservationists to save some habitat for salmon in streams burdened with 
industrial pollution and choked with logs. Although spraying has been tried as a weapon against 
the ubiquitous budworm, the areas affected have been relatively small and have not, as yet, 
included important spawning streams for salmon. But what happened to stream fish in an area 
observed by the Maine Department of Inland Fisheries and Game is perhaps a portent of things 

to come. 'Immediately after the 1958 spraying,' the Department reported, 'moribund suckers 
were observed in large numbers in Big Goddard Brook. These fish exhibited the typical 
symptoms of DDT poisoning; they swam erratically, gasped at the surface, and exhibited 
tremors and spasms. In the first five days after spraying, 668 dead suckers were collected from 
two blocking nets. Minnows and suckers were also killed in large numbers in Little Goddard, 
Carry, Alder, and Blake Brooks. Fish were often seen floating passively downstream in a 
weakened and moribund condition. In several instances, blind and dying trout were found 
floating passively downstream more than a week after spraying.' 

(The fact that DDT may cause blindness in fish is confirmed by various studies. A Canadian 
biologist who observed spraying on northern Vancouver Island in 1957 reported that cutthroat 
trout fingerlings could be picked out of the streams by hand, for the fish were moving sluggishly 
and made no attempt to escape. On examination, they were found to have an opaque white 
film covering the eye, indicating that vision had been impaired or destroyed. Laboratory studies 
by the Canadian Department of Fisheries showed that almost all fish [Coho salmon] not actually 
killed by exposure to low concentrations of DDT [3 parts per million] showed symptoms of 
blindness, with marked opacity of the lens.) Wherever there are great forests, modern methods 
of insect control threaten the fishes inhabiting the streams in the shelter of the trees. One of 
the best-known examples offish destruction in the United States took place in 1955, as a result 
of spraying in and near Yellowstone National Park. By the fall of that year, so many dead fish 
had been found in the Yellowstone River that sportsmen and Montana fish-and-game 
administrators became alarmed. About 90 miles of the river were affected. In one 300-yard 
length of shoreline, 600 dead fish were counted, including brown trout, whitefish, and suckers. 
Stream insects, the natural food of trout, had disappeared. Forest Service officials declared they 
had acted on advice that 1 pound of DDT to the acre was 'safe'. But the results of the spraying 
should have been enough to convince anyone that the advice had been far from sound. A 
cooperative study was begun in 1956 by the Montana Fish and Game Department and two 
federal agencies, the Fish and Wildlife Service and the Forest Service. Spraying in Montana that 
year covered 900,000 acres; 800,000 acres were also treated in 1957. The biologists therefore 
had no trouble finding areas for their study. Always, the pattern of death assumed a 
characteristic shape: the smell of DDT over the forests, an oil film on the water surface, dead 
trout along the shoreline. All fish analyzed, whether taken alive or dead, had stored DDT in their 
tissues. As in eastern Canada, one of the most serious effects of spraying was the severe 
reduction of food organisms. On many study areas aquatic insects and other stream-bottom 
fauna were reduced to a tenth of their normal populations. Once destroyed, populations of 
these insects, so essential to the survival of trout, take a long time to rebuild. Even by the end 
of the second summer after spraying, only meager quantities of aquatic insects had 
reestablished themselves, and on one stream— formerly rich in bottom fauna— scarcely any 
could be found. In this particular stream, game fish had been reduced by 80 per cent. 
The fish do not necessarily die immediately. In fact, delayed mortality may be more extensive 
than the immediate kill and, as the Montana biologists discovered, it may go unreported 
because it occurs after the fishing season. Many deaths occurred in the study streams among 
autumn spawning fish, including brown trout, brook trout, and whitefish. This is not surprising, 
because in time of physiological stress the organism, be it fish or man, draws on stored fat for 
energy. This exposes it to the full lethal effect of the DDT stored in the tissues. 

It was therefore more than clear that spraying at the rate of a pound of DDT to the acre posed a 
serious threat to the fishes in forest streams. Moreover, control of the budworm had not been 
achieved and many areas were scheduled for re-spraying. The Montana Fish and Game 
Department registered strong opposition to further spraying, saying it was 'not willing to 
compromise the sport fishery resource for programs of questionable necessity and doubtful 
success.' The Department declared, however, that it would continue to cooperate with the 
Forest Service 'in determining ways to minimize adverse effects.' 

But can such cooperation actually succeed in saving the fish? An experience in British Columbia 
speaks volumes on this point. There an outbreak of the black-headed budworm had been 
raging for several years. Forestry officials, fearing that another season's defoliation might result 
in severe loss of trees, decided to carry out control operations in 1957. There were many 
consultations with the Game Department, whose officials were concerned about the salmon 
runs. The Forest Biology Division agreed to modify the spraying program in every possible way 
short of destroying its effectiveness, in order to reduce risks to the fish. Despite these 
precautions, and despite the fact that a sincere effort was apparently made, in at least four 
major streams almost 100 per cent of the salmon were killed. 

In one of the rivers, the young of a run of 40,000 adult Coho salmon were almost completely 
annihilated. So were the young stages of several thousand steelhead trout and other species of 
trout. The Coho salmon has a three-year life cycle and the runs are composed almost entirely of 
fish of a single age group. Like other species of salmon, the Coho has a strong homing instinct, 
returning to its natal stream. There will be no repopulation from other streams. This means, 
then, that every third year the run of salmon into this river will be almost nonexistent, until 
such time as careful management, by artificial propagation or other means, has been able to 
rebuild this commercially important run. There are ways to solve this problem— to preserve the 
forests and to save the fishes, too. To assume that we must resign ourselves to turning our 
waterways into rivers of death is to follow the counsel of despair and defeatism. We must make 
wider use of alternative methods that are now known, and we must devote our ingenuity and 
resources to developing others. There are cases on record where natural parasitism has kept 
the budworm under control more effectively than spraying. Such natural control needs to be 
utilized to the fullest extent. There are possibilities of using less toxic sprays or, better still, of 
introducing microorganisms that will cause disease among the budworms without affecting the 
whole web of forest life. We shall see later what some of these alternative methods are and 
what they promise. 

Meanwhile, it is important to realize that chemical spraying of forest insects is neither the only 
way nor the best way. The pesticide threat to fishes may be divided into three parts. One, as we 
have seen, relates to the fishes of running streams in northern forests and to the single 
problem of forest spraying. It is confined almost entirely to the effects of DDT. Another is vast, 
sprawling, and diffuse, for it concerns the many different kinds of fishes— bass, sunfish, 
trappies, suckers, and others that inhabit many kinds of waters, still or flowing, in many parts of 
the country. It also concerns almost the whole gamut of insecticides now in agricultural use, 
although a few principal offenders like endrin, toxaphene, dieldrin, and heptachlor can easily be 
picked out. Still another problem must now be considered largely in terms of what we may 
logically suppose will happen in the future, because the studies that will disclose the facts are 
only beginning to be made. This has to do with the fishes of salt marshes, bays, and estuaries. 

It was inevitable that serious destruction of fishes would follow the widespread use of the new 
organic pesticides. 

Fishes are almost fantastically sensitive to the chlorinated hydrocarbons that make up the bulk 
of modern insecticides. And when millions of tons of poisonous chemicals are applied to the 
surface of the land, it is inevitable that some of them will find theirway into the ceaseless cycle 
of waters moving between land and sea. Reports of fish kills, some of disastrous proportions, 
have now become so common that the United States Public Health Service has set up an office 
to collect such reports from the states as an index of water pollution. This is a problem that 
concerns a great many people. Some 25 million Americans look to fishing as a major source of 
recreation and another 15 million are at least casual anglers. These people spend three billion 
dollars annually for licenses, tackle, boats, camping equipment, gasoline, and lodgings. 
Anything that deprives them of their sport will also reach out and affect a large number of 
economic interests. The commercial fisheries represent such an interest, and even more 
importantly, an essential source of food. Inland and coastal fisheries (excluding the offshore 
catch) yield an estimated three billion pounds a year. Yet, as we shall see, the invasion of 
streams, ponds, rivers, and bays by pesticides is now a threat to both recreational and 
commercial fishing. 

Examples of the destruction of fish by agricultural crop sprayings and dustings are everywhere 
to be found. In California, for example, the loss of some 60,000 game fish, mostly bluegill and 
other sunfish, followed an attempt to control the riceleaf miner with dieldrin. In Louisiana 30 or 
more instances of heavy fish mortality occurred in one year alone (1960) because of the use of 
endrin in the sugarcane fields. In Pennsylvania fish have been killed in numbers byendrin, used 
in orchards to combat mice. The use of chlordane for grasshopper control on the high western 
plains has been followed by the death of many stream fish. Probably no other agricultural 
program has been carried out on so large a scale as the dusting nd spraying of millions of acres 
of land in southern United States to control the fire ant. Heptachlor, the chemical chiefly used, 
is only slightly less toxic to fish than DDT. Dieldrin, another fire ant poison, has a well- 
documented history of extreme hazard to all aquatic life. Only endrin and toxaphene represent 
a greater danger to fish. All areas within the fire ant control area, whether treated with 
heptachlor or dieldrin, reported disastrous effects on aquatic life. A few excerpts will give the 
flavor of the reports from biologists who studied the damage: From Texas, 'Heavy loss of 
aquatic life despite efforts to protect canals', 'Dead fish. ..were present in all treated water", 
'Fish kill was heavy and continued for over 3 weeks'. From Alabama, 'Most adult fish were killed 
[in Wilcox County] within a few days after treatment,' 'The fish in temporary waters and small 
tributary streams appeared to have been completely eradicated.' 

In Louisiana, farmers complained of loss in farm ponds. Along one canal more than 500 dead 
fish were seen floating or lying on the bank on a stretch of less than a quarter of a mile. In 
another parish 150 dead sunfish could be found for every 4 that remained alive. Five other 
species appeared to have been wiped out completely. In Florida, fish from ponds in a treated 
area were found to contain residues of heptachlor and a derived chemical, heptachlor epoxide. 
Included among these fish were sunfish and bass, which of course are favorites of anglers and 
commonly find theirway to the dinner table. Yet the chemicals they contained are among those 
the Food and Drug Administration considers too dangerous for human consumption, even in 
minute quantities. So extensive were the reported kills of fish, frogs, and other life of the 

waters that the American Society of Ichthyologists and Herpetologists, a venerable scientific 
organization devoted to the study of fishes, reptiles, and amphibians, passed a resolution in 
1958 calling on the Department of Agriculture and the associated state agencies to cease 'aerial 
distribution of heptachlor, dieldrin, and equivalent poisons— before irreparable harm is done.' 
The Society called attention to the great variety of species of fish and other forms of life 
inhabiting the southeastern part of the United States, including species that occur nowhere else 
in the world. 'Many of these animals,' the Society warned, 'occupy only small areas and 
therefore might readily be completely exterminated.' Fishes of the southern states have also 
suffered heavily from insecticides used against cotton insects. The summer of 1950 was a 
season of disaster in the cotton-growing country of northern Alabama. Before that year, only 
limited use had been made of organic insecticides for the control of the boll weevil. But in 1950 
there were many weevils because of a series of mild winters, and so an estimated 80 to 95 per 
cent of the farmers, on the urging of the county agents, turned to the use of insecticides. The 
chemical most popular with the farmers was toxaphene, one of the most destructive to fishes. 
Rains were frequent and heavy that summer. They washed the chemicals into the strea ms, and 
as this happened the farmers applied more. An average acre of cotton that year received 63 
pounds of toxaphene. Some farmers used as much as 200 pounds per acre; one, in an 
extraordinary excess of zeal, applied more than a quarter of a ton to the acre. The results could 
easily have been foreseen. What happened in Flint Creek, flowing through 50 miles of Alabama 
cotton country before emptying into Wheeler Reservoir, was typical of the region. On August 1, 
torrents of rain descended on the Flint Creek watershed. In trickles, in rivulets, and finally in 
floods the water poured off the land into the streams. The water level rose six inches in Flint 
Creek. By the next morning it was obvious that a great deal more than rain had been carried 
into the stream. Fish swam about in aimless circles near the surface. Sometimes one would 
throw itself out of the water onto the bank. They could easily be caught; one farmer picked up 
several and took them to a spring-fed pool. There, in the pure water, these few recovered. But 
in the stream dead fish floated down all day. This was but the prelude to more, for each rain 
washed more of the insecticide into the river, killing more fish. The rain of August 10 resulted in 
such a heavy fish kill throughout the river that few remained to become victims of the next 
surge of poison into the stream, which occurred on August 15. But evidence of the deadly 
presence of the chemicals was obtained by placing test goldfish in cages in the river; they were 
dead within a day. 

The doomed fish of Flint Creek included large numbers of white crappies, a favorite among 
anglers. Dead bass and sunfish were also found, occurring abundantly in Wheeler Reservoir, 
into which the creek flows. All the rough-fish population of these waters was destroyed also— 
the carp, buffalo, drum, gizzard shad, and catfish. None showed signs of disease— only the 
erratic movements of the dying and a strange deep wine color of the gills. In the warm enclosed 
waters of farm ponds, conditions are very likely to be lethal for fish when insecticides are 
applied in the vicinity. As many examples show, the poison is carried in by rains and runoff from 
surrounding lands. Sometimes the ponds receive not only contaminated runoff but also a direct 
dose as crop-dusting pilots neglect to shut off the duster in passing over a pond. Even without 
such complications, normal agricultural use subjects fish to far heavier concentrations of 
chemicals than would be required to kill them. In other words, a marked reduction in the 
poundages used would hardly alter the lethal situation, for applications of over 0.1 pound per 

acre to the pond itself are generally considered hazardous. And the poison, once introduced, is 
hard to get rid of. One pond that had been treated with DDT to remove unwanted shiners 
remained so poisonous through repeated drainings and flushings that it killed 94 per cent of the 
sunfish with which it was later stocked. Apparently the chemical remained in the mud of the 
pond bottom. 

Conditions are evidently no better now than when the modern insecticides first came into use. 
The Oklahoma Wildlife Conservation Department stated in 1961 that reports of fish losses in 
farm ponds and small lakes had been coming in at the rate of at least one a week, and that such 
reports were increasing. The conditions usually responsible for these losses in Oklahoma were 
those made familiar by repetition over the years: the application of insecticides to crops, a 
heavy rain, and poison washed into the ponds. In some parts of the world the cultivation of fish 
in ponds provides an indispensable source of food. In such places the use of insecticides 
without regard for the effects on fish creates immediate problems. In Rhodesia, for example, 
the young of an important food fish, the Kafue bream, are killed by exposure to only 0.04 parts 
per million of DDT in shallow pools. Even smaller doses of many other insecticides would be 
lethal. The shallow waters in which these fish live are favorable mosquito-breeding places. The 
problem of controlling mosquitoes and at the same time conserving a fish important in the 
Central African diet has obviously not been solved satisfactorily. 

Milkfish farming in the Philippines, China, Vietnam, Thailand, Indonesia, and India faces a 
similar problem. The milkfish is cultivated in shallow ponds along the coasts of these countries. 
Schools of young suddenly appear in the coastal waters (from no one knows where) and are 
scooped up and placed in impoundments, where they complete their growth. So important is 
this fish as a source of animal protein for the rice-eating millions of Southeast Asia and India 
that the Pacific Science Congress has recommended an international effort to search for the 
now unknown spawning grounds, in order to develop the farming of these fish on a massive 
scale. Yet spraying has been permitted to cause heavy losses in existing impoundments. In the 
Philippines aerial spraying for mosquito control has cost pond owners dearly. In one such pond 
containing 120,000 milkfish, more than half the fish died after a spray plane had passed over, in 
spite of desperate efforts by the owner to dilute the poison by flooding the pond. 
One of the most spectacular fish kills of recent years occurred in the Colorado River below 
Austin, Texas, in 1961. Shortly after daylight on Sunday morning, January 15, dead fish 
appeared in the new Town Lake in Austin and in the river for a distance of about 5 miles below 
the lake. None had been seen the day before. On Monday there were reports of dead fish 50 
miles downstream. By this time it was clear that a wave of some poisonous substance was 
moving down in the river water. By January 21, fish were being killed 100 miles downstream 
near La Grange, and a week later the chemicals were doing their lethal work 200 miles below 
Austin. During the last week of January the locks on the Intracoastal Waterway were closed to 
exclude the toxic waters from Matagorda Bay and divert them into the Gulf of Mexico. 
Meanwhile, investigators in Austin noticed an odor associated with the insecticides chlordane 
and toxaphene. It was especially strong in the discharge from one of the storm sewers. This 
sewer had in the past been associated with trouble from industrial wastes, and when officers of 
the Texas Game and Fish Commission followed it back from the lake, they noticed an odor like 
that of benzene hexachloride at all openings as far back as a feeder line from a chemical plant. 
Among the major products of this plant were DDT, benzene hexachloride, chlordane, and 

toxaphene, as well as smaller quantities of other insecticides. The manager of the plant 
admitted that quantities of powdered insecticide had been washed into the storm sewer 
recently and, more significantly, he acknowledged that such disposal of insecticide spillage and 
residues had been common practice for the past 10 years. On searching further, the fishery 
officers found other plants where rains or ordinary clean-up waters would carry insecticides 
into the sewer. The fact that provided the final link in the chain, however, was the discovery 
that a few days before the water in lake and river became lethal to fish the entire storm-sewer 
system had been flushed out with several million gallons of water under high pressure to clear 
it of debris. This flushing had undoubtedly released insecticides lodged in the accumulation of 
gravel, sand, and rubble and carried them into the lake and thence to the river, where chemical 
tests later established their presence. As the lethal mass drifted down the Colorado it carried 
death before it. For 140 miles downstream from the lake the kill offish must have been almost 
complete, for when seines were used later in an effort to discover whether any fish had 
escaped they came up empty. Dead fish of 27 species were observed, totaling about 1000 
pounds to a mile of riverbank. There were channel cats, the chief game fish of the river. There 
were blue and flathead catfish, bullheads, four species of sunfish, shiners, dace, stone rollers, 
largemouth bass, carp, mullet, suckers. There were eels, gar, carp, river carpsuckers, gizzard 
shad, and buffalo. Among them were some of the patriarchs of the river, fish that by their size 
must have been of great age— many flathead catfish weighing over 25 pounds, some of 60 
pounds reportedly picked up by local residents along the river, and a giant blue catfish officially 
recorded as weighing 84 pounds. The Game and Fish Commission predicted that even without 
further pollution the pattern of the fish population of the river would be altered for years. 
Some species— those existing at the limits of their natural range— might never be able to re- 
establish themselves, and the others could do so only with the aid of extensive stocking 
operations by the state. This much of the Austin fish disaster is known, but there was almost 
certainly a sequel. The toxic river water was still possessed of its death-dealing power after 
passing more than 200 miles downstream. It was regarded as too dangerous to be admitted to 
the waters of Matagorda Bay, with its oyster beds and shrimp fisheries, and so the whole toxic 
outflow was diverted to the waters of the open Gulf. What were its effects there? And what of 
the outflow of scores of other rivers, carrying contaminants perhaps equally lethal? 
At present our answers to these questions are for the most part only conjectures, but there is 
growing concern about the role of pesticide pollution in estuaries, salt marshes, bays, and other 
coastal waters. Not only do these areas receive the contaminated discharge of rivers but all too 
commonly they are sprayed directly in efforts to control mosquitoes or other insects. 
Nowhere has the effect of pesticides on the life of salt marshes, estuaries, and all quiet inlets 
from the sea been more graphically demonstrated than on the eastern coast of Florida, in the 
Indian River country. There, in the spring of 1955, some 2000 acres of salt marsh in St. Lucie 
County were treated with dieldrin in an attempt to eliminate the larvae of the sandfly. The 
concentration used was one pound of active ingredient to the acre. The effect on the life of the 
waters was catastrophic. Scientists from the Entomology Research Center of the State Board of 
Health surveyed the carnage after the spraying and reported that the fish kill was 'substantially 
complete'. Everywhere dead fishes littered the shores. From the air sharks could be seen 
moving in, attracted by the helpless and dying fishes in the water. No species was spared. 
Among the dead were mullets, snook, mojarras, gambusia. 

The minimum immediate overall kill throughout the marshes, exclusive of the Indian River 
shoreline, was 20-30 tons of fishes, or about 1,175,000 fishes, of at least 30 species [reported R. 
W. Harrington, Jr. and W.L. Bidlingmayer of the survey team]. Mollusks seemed to be 
unharmed by dieldrin. Crustaceans were virtually exterminated throughout the area. The entire 
aquatic crab population was apparently destroyed and the fiddler crabs, all but annihilated, 
survived temporarily only in patches of marsh evidently missed by the pellets. The larger game 
and food fishes succumbed most rapidly.. .Crabs net upon and destroyed the moribund fishes, 
but the next day were dead themselves. Snails continued to devour fish carcasses. After two 
weeks, no trace remained of the litter of dead fishes. The same melancholy picture was painted 
by the late Dr. Herbert R. Mills from his observations in Tampa Bay on the opposite coast of 
Florida, where the National Audubon Society operates a sanctuary for seabirds in the area 
including Whiskey Stump Key. The sanctuary ironically became a poor refuge after the local 
health authorities undertook a campaign to wipe out the salt-marsh mosquitoes. Again fishes 
and crabs were the principal victims. The fiddler crab, that small and picturesque crustacean 
whose hordes move over mud flats or sand flats like grazing cattle, has no defense against the 
sprayers. After successive sprayings during the summer and fall months (some areas were 
sprayed as many as 16 times), the state of the fiddler crabs was summed up by Dr. Mills: 'A 
progressive scarcity of fiddlers had by this time become apparent. Where there should have 
been in the neighborhood of 100,000 fiddlers under the tide and weather conditions of the day 
[October 12] there were not over 100 which could be seen anywhere on the beach, and these 
were all dead or sick, quivering, twitching, stumbling, scarcely able to crawl; although in 
neighboring unsprayed areas fiddlers were plentiful.' 

The place of the fiddler crab in the ecology of the world it inhabits is a necessary one, not easily 
filled. It is an important source of food for many animals. Coastal raccoons feed on them. So do 
marsh-inhabiting birds like the clapper rail, shore- birds, and even visiting seabirds. In the New 
Jersey salt marsh sprayed with DDT, the normal population of laughing gulls was decreased by 
85 per cent for several weeks, presumably because the birds could not find sufficient food after 
the spraying. The marsh fiddlers are important in other ways as well, being useful scavengers 
and aerating the mud of the marshes by their extensive burrowings. They also furnish 
quantities of bait for fishermen. The fiddler crab is not the only creature of tidal marsh and 
estuary to be threatened by pesticides; others of more obvious importance to man are 
endangered. The famous blue crab of the Chesapeake Bay and other Atlantic Coast areas is an 
example. These crabs are so highly susceptible to insecticides that every spraying of creeks, 
ditches, and ponds in tidal marshes kills most of the crabs living there. Not only do the local 
crabs die, but others moving into a sprayed area from the sea succumb to the lingering poison. 
And sometimes poisoning may be indirect, as in the marshes near Indian River, where 
scavenger crabs attacked the dying fishes, but soon themselves succumbed to the poison. Less 
is known about the hazard to the lobster. However, it belongs to the same group of arthropods 
as the blue crab, has essentially the same physiology, and would presumably suffer the same 
effects. This would be true also of the stone crab and other crustaceans which have direct 
economic importance as human food. 

The inshore waters— the bays, the sounds, the river estuaries, the tidal marshes— form an 
ecological unit of the utmost importance. They are linked so intimately and indispensably with 
the lives of many fishes, mollusks, and crustaceans that were they no longer habitable these 

seafoods would disappear from our tables. Even among fishes that range widely in coastal 
waters, many depend upon protected inshore areas to serve as nursery and feeding grounds for 
their young. Baby tarpon are abundant in all that labyrinth of mangrove-lined streams and 
canals bordering the lower third of the western coast of Florida. On the Atlantic Coast the sea 
trout, croaker, spot, and drum spawn on sandy shoals off the inlets between the islands or 
'banks' that lie like a protective chain off much of the coast south of New York. The young fish 
hatch and are carried through the inlets by the tides. In the bays and sounds— Currituck, 
Pamlico, Bogue, and many others— they find abundant food and grow rapidly. Without these 
nursery areas of warm protected, food-rich waters the populations of these and many other 
species could not be maintained. Yet we are allowing pesticides to enter them via the rivers and 
by direct spraying over bordering marshlands. And the early stages of these fishes, even more 
than the adults, are especially susceptible to direct chemical poisoning. Shrimp, too, depend on 
inshore feeding grounds for their young. One abundant and widely ranging species supports the 
entire commercial fishery of the southern Atlantic and Gulf states. Although spawning occurs at 
sea, the young come into the estuaries and bays when a few weeks old to undergo successive 
molts and changes of form. There they remain from May or June until fall, feeding on the 
bottom detritus. In the entire period of their inshore life, the welfare of the shrimp populations 
and of the industry they support depends upon favorable conditions in the estuaries. 
Do pesticides represent a threat to the shrimp fisheries and to the supply for the markets? The 
answer may be contained in recent laboratory experiments carried out by the Bureau of 
Commercial Fisheries. The insecticide tolerance of young commercial shrimp just past larval life 
was found to be exceedingly low— measured in parts per billion instead of the more commonly 
used standard of parts per million. For example, half the shrimp in one experiment were killed 
by dieldrin at a concentration of only 15 per billion. Other chemicals were even more toxic. 
Endrin, always one of the most deadly of the pesticides, killed half the shrimp at a 
concentration of only half of one part per billion. The threat to oysters and clams is multiple. 
Again, the young stages are most vulnerable. These shellfish inhabit the bottoms of bays and 
sounds and tidal rivers from New England to Texas and sheltered areas of the Pacific Coast. 
Although sedentary in adult life, they discharge their spawn into the sea, where the young are 
free-living for a period of several weeks. On a summer day a fine-meshed tow net drawn behind 
a boat will collect, along with the other drifting plant and animal life that make up the plankton, 
the infinitely small, fragile-as-glass larvae of oysters and clams. No larger than grains of dust, 
these transparent larvae swim about in the surface waters, feeding on the microscopic plant life 
of the plankton. If the crop of minute sea vegetation fails, the young shellfish will starve. Yet 
pesticides may well destroy substantial quantities of plankton. Some of the herbicides in 
common use on lawns, cultivated fields, and roadsides and even in coastal marshes are 
extraordinarily toxic to the plant plankton which the larval mollusks use as food— some at only 
a few parts per billion. 

The delicate larvae themselves are killed by very small quantities of many of the common 
insecticides. Even exposures to less than lethal quantities may in the end cause death of the 
larvae, for inevitably the growth rate is retarded. This prolongs the period the larvae must 
spend in the hazardous world of the plankton and so decreases the chance they will live to 
adulthood. For adult mollusks there is apparently less danger of direct poisoning, at least by 
some of the pesticides. This is not necessarily reassuring, however. Oysters and clams may 

concentrate these poisons in their digestive organs and other tissues. Both types of shellfish are 
normally eaten whole and sometimes raw. Dr. Philip Butler of the Bureau of Commercial 
Fisheries has pointed out an ominous parallel in that we may find ourselves in the same 
situation as the robins. The robins, he reminds us, did not die as a direct result of the spraying 
of DDT. They died because they had eaten earthworms that had already concentrated the 
pesticides in their tissues. . . . 

Although the sudden death of thousands of fish or crustaceans in some stream or pond as the 
direct and visible effect of insect control is dramatic and alarming, these unseen and as yet 
largely unknown and unmeasurable effects of pesticides reaching estuaries indirectly in streams 
and rivers may in the end be more disastrous. The whole situation is beset with questions for 
which there are at present no satisfactory answers. We know that pesticides contained in 
runoff from farms and forests are now being carried to the sea in the waters of many and 
perhaps all of the major rivers. But we do not know the identity of all the chemicals or their 
total quantity, and we do not presently have any dependable tests for identifying them in highly 
diluted state once they have reached the sea. Although we know that the chemicals have 
almost certainly undergone change during the long period of transit, we do not know whether 
the altered chemical is more toxic than the original or less. Another almost unexplored area is 
the question of interactions between chemicals, a question that becomes especially urgent 
when they enter the marine environment where so many different minerals are subjected to 
mixing and transport. All of these questions urgently require the precise answers that only 
extensive research can provide, yet funds for such purposes are pitifully small. 
The fisheries of fresh and salt water are a resource of great importance, involving the interests 
and the welfare of a very large number of people. That they are now seriously threatened by 
the chemicals entering our waters can no longer be doubted. If we would divert to constructive 
research even a small fraction of the money spent each year on the development of ever more 
toxic sprays, we could find ways to use less dangerous materials and to keep poisons out of our 
waterways. When will the public become sufficiently aware of the facts to demand such action? 

10. Indiscriminately from the Skies 

FROM SMALL BEGINNINGS over farmlands and forests the scope of aerial spraying has 
widened and its volume has increased so that it has become what a British ecologist recently 
called 'an amazing rain of death' upon the surface of the earth. Our attitude towards poisons 
has undergone a subtle change. Once they were kept in containers marked with skull and 
crossbones; the infrequent occasions of their use were marked with utmost care that they 
should come in contact with the target and with nothing else. With the development of the 
new organic insecticides and the abundance of surplus planes after the Second World War, all 
this was forgotten. Although today's poisons are more dangerous than any known before, they 
have amazingly become something to be showered down indiscriminately from the skies. Not 
only the target insect or plant, but anything— human or no nhu man— within range of the 
chemical fallout may know the sinister touch of the poison. Not only forests and cultivated 
fields are sprayed, but towns and cities as well. 

A good many people now have misgivings about the aerial distribution of lethal chemicals over 
millions of acres, and two mass-spraying campaigns undertaken in the late 1950s have done 
much to increase these doubts. These were the campaigns against the gypsy moth in the 
northeastern states and the fire ant in the South. Neither is a native insect but both have been 
in this country for many years without creating a situation calling for desperate measures. Yet 
drastic action was suddenly taken against them, under the end-justifies-the-means philosophy 
that has too long directed the control divisions of our Department of Agriculture. 
The gypsy moth program shows what a vast amount of damage can he done when reckless 
large-scale treatment is substituted for local and moderate control. The campaign against the 
fire ant is a prime example of a campaign based on gross exaggeration of the need for control, 
blunderingly launched without scientific knowledge of the dosage of poison required to destroy 
the target or of its effects on other life. Neither program has achieved its goal. . . . 
The gypsy moth, a native of Europe, has been in the United States for nearly a hundred years. In 
1869 a French scientist, Leopold Trouvelot, accidentally allowed a few of these moths to escape 
from his laboratory in Medford, Massachusetts, where he was attempting to cross them with 
silkworms. Little by little the gypsy moth has spread throughout New England. The primary 
agent of its progressive spread is the wind; the larval, or caterpillar, stage is extremely light and 
can be carried to considerable heights and over great distances. Another means is the shipment 
of plants carrying the egg masses, the form in which the species exists over winter. The gypsy 
moth, which in its larval stage attacks the foliage of oak trees and a few other hardwoods for a 
few weeks each spring, now occurs in all the New England states. It also occurs sporadically in 
New Jersey, where it was introduced in 1911 on a shipment of spruce trees from Holland, and 
in Michigan, where its method of entry is not known. The New England hurricane of 1938 
carried it into Pennsylvania and New York, but the Adirondacks have generally served as a 
barrier to its westward advance, being forested with species not attractive to it. 
The task of confining the gypsy moth to the northeastern corner of the country has been 
accomplished by a variety of methods, and in the nearly one hundred years since its arrival on 
this continent the fear that it would invade the great hardwood forests of the southern 
Appalachians has not been justified. Thirteen parasites and predators were imported from 

abroad and successfully established in New England. The Agriculture Department itself has 
credited these importations with appreciably reducing the frequency and destructiveness of 
gypsy moth outbreaks. This natural control, plus quarantine measures and local spraying, 
achieved what the Department in 1955 described as 'outstanding restriction of distribution and 
damage'. Yet only a year after expressing satisfaction with the state of affairs, its Plant Pest 
Control Division embarked on a program calling for the blanket spraying of several million acres 
a year with the announced intention of eventually 'eradicating' the gypsy moth. ('Eradication' 
means the complete and final extinction or extermination of a species throughout its range. Yet 
as successive programs have failed, the Department has found it necessary to speak of second 
or third 'eradications' of the same species in the same area.) 

The Department's all-out chemical war on the gypsy moth began on an ambitious scale. In 1956 
nearly a million acres were sprayed in the states of Pennsylvania, New Jersey, Michigan, and 
New York. Many complaints of damage were made by people in the sprayed areas. 
Conservationists became increasingly disturbed as the pattern of spraying huge areas began to 
establish itself. When plans were announced for spraying 3 million acres in 1957 opposition 
became even stronger. State and federal agriculture officials characteristically shrugged off 
individual complaints as unimportant. The Long Island area included within the gypsy moth 
spraying in 1957 consisted chiefly of heavily populated towns and suburbs and of some coastal 
areas with bordering salt marsh. Nassau County, Long Island, is the most densely settled county 
in New York apart from New York City itself. In what seems the height of absurdity, the 'threat 
of infestation of the New York City metropolitan area' has been cited as an important 
justification of the program. The gypsy moth is a forest insect, certainly not an inhabitant of 
cities. Nor does it live in meadows, cultivated fields, gardens, or marshes. Nevertheless, the 
planes hired by the United States Department of Agriculture and the New York Department of 
Agriculture and Markets in 1957 showered down the prescribed DDT-in-fuel-oil with 
impartiality. They sprayed truck gardens and dairy farms, fish ponds and salt marshes. They 
sprayed the quarter-acre lots of suburbia, drenching a housewife making a desperate effort to 
cover her garden before the roaring plane reached her, and showering insecticide over children 
at play and commuters at railway stations. At Setauket a fine quarter horse drank from a trough 
in a field which the planes had sprayed; ten hours later it was dead. Automobiles were spotted 
with the oily mixture; flowers and shrubs were ruined. Birds, fish, crabs, and useful insects were 

A group of Long Island citizens led by the world-famous ornithologist Robert Cushman Murphy 
had sought a court injunction to prevent the 1957 spraying. Denied a preliminary injunction, 
the protesting citizens had to suffer the prescribed drenching with DDT, but thereafter 
persisted in efforts to obtain a permanent injunction. But because the act had already been 
performed the courts held that the petition for an injunction was 'moot'. The case was carried 
all the way to the Supreme Court, which declined to hea r it. Justice William O. Douglas, strongly 
dissenting from the decision not to review the case, held that 'the alarms that many experts 
and responsible officials have raised about the perils of DDT underline the public importance of 
this case.' 

The suit brought by the Long Island citizens at least served to focus public attention on the 
growing trend to mass application of insecticides, and on the power and inclination of the 
control agencies to disregard supposedly inviolate property rights of private citizens. 

The contamination of milk and of farm produce in the course of the gypsy moth spraying came 
as an unpleasant surprise to many people. What happened on the 200-acre Waller farm in 
northern Westchester County, New York, was revealing. Mrs. Waller had specifically requested 
Agriculture officials not to spray her property, because it would be impossible to avoid the 
pastures in spraying the woodlands. She offered to have the land checked for gypsy moths and 
to have any infestation destroyed by spot spraying. Although she was assured that no farms 
would be sprayed, her property received two direct sprayings and, in addition, was twice 
subjected to drifting spray. Milk samples taken from the Wallers' purebred Guernsey cows 48 
hours later contained DDT in the amount of 14 parts per million. Forage samples from fields 
where the cows had grazed were of course contaminated also. Although the county Health 
Department was notified, no instructions were given that the milk should not be marketed. This 
situation is unfortunately typical of the lack of consumer protection that is all too common. 
Although the Food and Drug Administration permits no residues of pesticides in milk, its 
restrictions are not only inadequately policed but they apply solely to interstate shipments. 
State and county officials are under no compulsion to follow the federal pesticides tolerances 
unless local laws happen to conform— and they seldom do. 

Truck gardeners also suffered. Some leaf crops were so burned and spotted as to be 
unmarketable. Others carried heavy residues; a sample of peas analyzed at Cornell University's 
Agricultural Experiment Station contained 14 to 20 parts per million of DDT. The legal maximum 
is 7 parts per million. Growers therefore had to sustain heavy losses or find themselves in the 
position of selling produce carrying illegal residues. Some of them sought and collected 
damages. As the aerial spraying of DDT increased, so did the number of suits filed in the courts. 
Among them were suits brought by beekeepers in several areas of New York State. Even before 
the 1957 spraying, the beekeepers had suffered heavily from use of DDT in orchards. 'Up to 
1953 I had regarded as gospel everything that emanated from the U.S. Department of 
Agriculture and the agricultural colleges,' one of them remarked bitterly. But in May of that 
year this man lost 800 colonies after the state had sprayed a large area. So widespread and 
heavy was the loss that 14 other beekeepers joined him in suing the state for a quarter of a 
million dollars in damages. Another beekeeper, whose 400 colonies were incidental targets of 
the 1957 spray, reported that 100 per cent of the field force of bees (the workers out gathering 
nectar and pollen for the hives) had been killed in forested areas and up to 50 per cent in 
farming areas sprayed less intensively. 

'It is a very distressful thing,' he wrote, 'to walk into a yard in May and not hear a bee buzz.' 
The gypsy moth programs were marked by many acts of irresponsibility. Because the spray 
planes were paid by the gallon rather than by the acre there was no effort to be conservative, 
and many properties were sprayed not once but several times. Contracts for aerial spraying 
were in at least one case awarded to an out-of-state firm with no local address, which had not 
complied with the legal requirement of registering with state officials for the purpose of 
establishing legal responsibility. In this exceedingly slippery situation, citizens who suffered 
direct financial loss from damage to apple orchards or bees discovered that there was no one to 
sue. After the disastrous 1957 spraying the program was abruptly and drastically curtailed, with 
vague statements about 'evaluating' previous work and testing alternative insecticides. Instead 
of the 3 1 /4 million acres sprayed in 1957, the treated areas fell to Vi million in 1958 and to about 

100,000 acres in 1959, 1960, and 1961. During this interval, the control agencies must have 
found news from Long Island disquieting. The gypsy moth had reappeared there in numbers. 
The expensive spraying operation that had cost the Department dearly in public confidence and 
good will— the operation that was intended to wipe out the gypsy moth for ever— had in reality 
accomplished nothing at all. . . . 

Meanwhile, the Department's Plant Pest Control men had temporarily forgotten gypsy moths, 
for they had been busy launching an even more ambitious program in the South. The word 
'eradication' still came easily from the Department's mimeograph machines; this time the press 
releases were promising the eradication of the fire ant. The fire ant, an insect named for its 
fiery sting, seems to have entered the United States from South America by way of the port of 
Mobile, Alabama, where it was discovered shortly after the end of the First World War. By 1928 
it had spread into the suburbs of Mobile and thereafter continued an invasion that has now 
carried it into most of the southern states. During most of the forty-odd years since its arrival in 
the United States the fire ant seems to have attracted little attention. The states where it was 
most abundant considered it a nuisance, chiefly because it builds large nests or mounds a foot 
or more high. These may hamper the operation of farm machinery. But only two states listed it 
among their 20 most important insect pests, and these placed it near the bottom of the list. No 
official or private concern seems to have been felt about the fire ant as a menace to crops or 
livestock. With the development of chemicals of broad lethal powers, there came a sudden 
change in the official attitude toward the fire ant. In 1957 the United States Department of 
Agriculture launched one of the most remarkable publicity campaigns in its history. The fire ant 
suddenly became the target of a barrage of government releases, motion pictures, and 
government-inspired stories portraying it as a despoiler of southern agriculture and a killer of 
birds, livestock, and man. A mighty campaign was announced, in which the federal government 
in cooperation with the afflicted states would ultimately treat some 20,000,000 acres in nine 
southern states. 'United States pesticide makers appear to have tapped a sales bonanza in the 
increasing numbers of broad-scale pest elimination programs conducted by the U.S. 
Department of Agriculture,' cheerfully reported one trade journal in 1958, as the fire ant 
program got underway. 

Never has any pesticide program been so thoroughly and deservedly damned by practically 
everyone except the beneficiaries of this 'sales bonanza'. It is an outstanding example of an ill- 
conceived, badly executed, and thoroughly detrimental experiment in the mass control of 
insects, an experiment so expensive in dollars, in destruction of animal life, and in loss of public 
confidence in the Agriculture Department that it is incomprehensible that any funds should still 
be devoted to it. 

Congressional support of the project was initially won by representations that were later 
discredited. The fire ant was pictured as a serious threat to southern agriculture through 
destruction of crops and to wildlife because of attacks on the young of ground-nesting birds. Its 
sting was said to make it a serious menace to human health. Just how sound were these claims? 
The statements made by Department witnesses seeking appropriations were not in accord with 
those contained in key publications of the Agriculture Department. The 1957 bulletin Insecticide 
Recommendations. ..for the Control of Insects Attacking Crops and Livestock did not so much as 
mention the fire ant— an extraordinary omission if the Department believes its own 
propaganda. Moreover, its encyclopedic Yearbook for 1952, which was devoted to insects, 

contained only one short paragraph on the fire ant out of its half-million words of text. Against 
the Department's undocumented claim that the fire ant destroys crops and attacks livestock is 
the careful study of the Agricultural Experiment Station in the state that has had the most 
intimate experience with this insect, Alabama. According to Alabama scientists, 'damage to 
plants in general is rare.' Dr. F. S. Arant, an entomologist at the Alabama Polytechnic Institute 
and in 1961 president of the Entomological Society of America, states that his department 'has 
not received a single report of damage to plants by ants in the past five years. ..No damage to 
livestock has been observed.' These men, who have actually observed the ants in the field and 
in the laboratory, say that the fire ants feed chiefly on a variety of other insects, many of them 
considered harmful to man's interests. Fire ants have been observed picking larvae of the boll 
weevil off cotton. Their mound-building activities serve a useful purpose in aerating and 
draining the soil. The Alabama studies have been substantiated by investigations at the 
Mississippi State University, and are far more impressive than the Agriculture Department's 
evidence, apparently based either on conversations with farmers, who may easily mistake one 
ant for another, or on old research. Some entomologists believe that the ant's food habits have 
changed as it has become more abundant, so that observations made several decades ago have 
little value now. The claim that the ant is a menace to health and life also bears considerable 
modification. The Agriculture Department sponsored a propaganda movie (to gain support for 
its program) in which horror scenes were built around the fire ant's sting. Admittedly this is 
painful and one is well advised to avoid being stung, just as one ordinarily avoids the sting of 
wasp or bee. Severe reactions may occasionally occur in sensitive individuals, and medical 
literature records one death possibly, though not definitely, attributable to fire ant venom. In 
contrast to this, the Office of Vital Statistics records 33 deaths in 1959 alone from the sting of 
bees and wasps. Yet no one seems to have proposed 'eradicating' these insects. Again, local 
evidence is most convincing. Although the fire ant has inhabited Alabama for 40 years and is 
most heavily concentrated there, the Alabama State Health Officer declares that 'there has 
never been recorded in Alabama a human death resulting from the bites of imported fire ants,' 
and considers the medical cases resulting from the bites of fire ants 'incidental'. Ant mounds on 
lawns or playgrounds may create a situation where children are likely to be stung, but this is 
hardly an excuse for drenching millions of acres with poisons. These situations can easily be 
handled by individual treatment of the mounds. 

Damage to game birds was also alleged, without supporting evidence. Certainly a man well 
qualified to speak on this issue is the leader of the Wildlife Research Unit at Auburn, Alabama, 
Dr. Maurice F. Baker, who has had many years' experience in the area. But Dr. Baker's opinion 
is directly opposite to the claims of the Agriculture Department. He declares: 'In south Alaba ma 
and northwest Florida we are able to have excellent hunting and bobwhite populations 
coexistent with heavy populations of the imported fire ant. the almost 40 years that south 
Alabama has had the fire ant, game populations have shown a steady and very substantial 
increase. Certainly, if the imported fire ant were a serious menace to wildlife, these conditions 
could not exist.' What would happen to wildlife as a result of the insecticide used against the 
ants was another matter. The chemicals to be used were dieldrin and heptachlor, both 
relatively new. There was little experience of field use for either, and no one knew what their 
effects would be on wild birds, fishes, or mammals when applied on a massive scale. It was 
known, however, that both poisons were many times more toxic than DDT, which had been 

used by that time for approximately a decade, and had killed some birds and many fish even at 
a rate of 1 pound per acre. And the dosage of dieldrin and heptachlor was heavier— 2 pounds to 
the acre under most conditions, or 3 pounds of dieldrin if the white-fringed beetle was also to 
be controlled. In terms of their effects on birds, the prescribed use of heptachlor would be 
equivalent to 20 pounds of DDT to the acre, that of dieldrin to 120 pounds! 
Urgent protests were made by most of the state conservation departments, by national 
conservation agencies, and by ecologists and even by some entomologists, calling upon the 
then Secretary of Agriculture, Ezra Benson, to delay the program at least until some research 
had been done to determine the effects of heptachlor and dieldrin on wild and domestic 
animals and to find the minimum amount that would control the ants. The protests were 
ignored and the program was launched in 1958. A million acres were treated the first year. It 
was clear that any research would be in the nature of a post mortem. 

As the program continued, facts began to accumulate from studies made by biologists of state 
and federal wildlife agencies and several universities. The studies revealed losses running all the 
way up to complete destruction of wildlife on some of the treated areas. Poultry, livestock, and 
pets were also killed. The Agriculture Department brushed away all evidence of damage as 
exaggerated and misleading. 

The facts, however, continue to accumulate. In Hardin County, Texas, for example, opossums, 
armadillos, and an abundant raccoon population virtually disappeared after the chemical was 
laid down. Even the second autumn after treatment these animals were scarce. The few 
raccoons then found in the area carried residues of the chemical in their tissues. Dead birds 
found in the treated areas had absorbed or swallowed the poisons used against the fire ants, a 
fact clearly shown by chemical analysis of their tissues. (The only bird surviving in any numbers 
was the house sparrow, which in other areas too has given some evidence that it may be 
relatively immune.) On a tract in Alabama treated in 1959 half of the birds were killed. Species 
that live on the ground or frequent low vegetation suffered 100 percent mortality. Even a 
year after treatment, a spring die-off of songbirds occurred and much good nesting territory lay 
silent and unoccupied. In Texas, dead blackbirds, dickcissels, and meadowlarks were found at 
the nests, and many nests were deserted. When specimens of dead birds from Texas, Louisiana, 
Alabama, Georgia, and Florida were sent to the Fish and Wildlife Service for analysis, more than 
90 per cent were found to contain residues of dieldrin or a form of heptachlor, in amounts up 
to 38 parts per million. 

Woodcocks, which winter in Louisiana but breed in the North, now carry the taint of the fire ant 
poisons in their bodies. The source of this contamination is clear. Woodcocks feed heavily on 
earthworms, which they probe for with their long bills. Surviving worms in Louisiana were 
found to have as much as 20 parts per million of heptachlor in their tissues 6 to 10 months after 
treatment of the area. A year later they had up to 10 parts per million. The consequences of the 
sublethal poisoning of the woodcock are now seen in a marked decline in the proportion of 
young birds to adults, first observed in the season after fire ant treatments began. Some of the 
most upsetting news for southern sportsmen concerned the bobwhite quail. This bird, a ground 
nesterand forager, was all but eliminated on treated areas. In Alabama, for example, biologists 
of the Alabama Cooperative Wildlife Research Unit conducted a preliminary census of the quail 
population in a 3600-acre area that was scheduled for treatment. Thirteen resident coveys— 
121 quail— ranged over the area. Two weeks after treatment only dead quail could be found. All 

specimens sent to the Fish and Wildlife Service for analysis were found to contain insecticides 
in amounts sufficient to cause their death. The Alabama findings were duplicated in Texas, 
where a 2500-acre area treated with heptachlor lost all of its quail. Along with the quail went 
90 per cent of the songbirds. Again, analysis revealed the presence of heptachlor in the tissues 
of dead birds. 

In addition to quail, wild turkeys were seriously reduced by the fire ant program. Although 80 
turkeys had been counted on an area in Wilcox County, Alabama, before heptachlor was 
applied, none could be found the summer after treatment— none, that is, except a clutch of 
unhatched eggs and one dead poult. The wild turkeys may have suffered the same fate as their 
domestic brethren, for turkeys on farms in the area treated with chemicals also produced few 
young. Few eggs hatched and almost no young survived. This did not happen on nearby 
untreated areas. The fate of the turkeys was by no means unique. One of the most widely 
known and respected wildlife biologists in the country, Dr. Clarence Cottam, called on some of 
the farmers whose property had been treated. Besides remarking that 'all the little tree birds' 
seemed to have disappeared after the land had been treated, most of these people reported 
losses of livestock, poultry, and household pets. One man was 'irate against the control 
workers,' Dr. Cottam reported, 'as he said he buried or otherwise disposed of 19 carcasses of 
his cows that had been killed by the poison and he knew of three or four additional cows that 
died as a result of the same treatment. Calves died that had been given only milk since birth.' 
The people Dr. Cottam interviewed were puzzled by what had happened in the months 
following the treatment of their land. One woman told him she had set several hens after the 
surrounding land had been covered with poison, 'and for reasons she did not understand very 
few young were hatched or survived.' Another farmer 'raises hogs and for fully nine months 
after the broadcast of poisons, he could raise no young pigs. The litters were born dead or they 
died after birth.' A similar report came from another, who said that out of 37 litters that might 
have numbered as many as 250 young, only 31 little pigs survived. This man had also been quite 
unable to raise chickens since the land was poisoned. The Department of Agriculture has 
consistently denied livestock losses related to the fire ant program. However, a veterinarian in 
Bainbridge, Georgia, Dr. Otis L. Poitevint, who was called upon to treat many of the affected 
animals, has summarized his reasons for attributing the deaths to the insecticide as follows. 
Within a period of two weeks to several months after the fire ant poison was applied, cattle, 
goats, horses, chickens, and birds and other wildlife began to suffer an often fatal disease of the 
nervous system. It affected only animals that had access to contaminated food or water. 
Stabled animals were not affected. The condition was seen only in areas treated for fire ants. 
Laboratory tests for disease were negative. The symptoms observed by Dr. Poitevint and other 
veterinarians were those described in authoritative texts as indicating poisoning by dieldrin or 

Dr. Poitevint also described an interesting case of a two-month-old calf that showed symptoms 
of poisoning by heptachlor. The animal was subjected to exhaustive laboratory tests. The only 
significant finding was the discovery of 79 parts per million of heptachlor in its fat. But it was 
five months since the poison had been applied. Did the calf get it directly from grazing or 
indirectly from its mother's milk or even before birth? 'If from the milk,' asked Dr. Poitevint, 
'why were not special precautions taken to protect our children who drank milk from local 
dairies?' Dr. Poitevint's report brings up a significant problem about the contamination of milk. 

The area included in the fire ant program is predominantly fields and croplands. What about 
the dairy cattle that graze on these lands? In treated fields the grasses will inevitably carry 
residues of heptachlor in one of its forms, and if the residues are eaten by the cows the poison 
will appear in the milk. This direct transmission into milk had been demonstrated 
experimentally for heptachlor in 1955, long before the control program was undertaken, and 
was later reported fordieldrin, also used in the fire ant program. 

The Department of Agriculture's annual publications now list heptachlor and dieldrin among 
the chemicals that make forage plants unsuitable for feeding to dairy animals or animals being 
finished for slaughter, yet the control divisions of the Department promote programs that 
spread heptachlor and dieldrin over substantial areas of grazing land in the South. Who is 
safeguarding the consumer to see that no residues of dieldrin or heptachlor are appearing in 
milk? The United States Department of Agriculture would doubtless answer that it has advised 
farmers to keep milk cows out of treated pastures for 30 to 90 days. Given the small size of 
many of the farms and the largescale nature of the program— much of the chemical applied by 
planes— it is extremely doubtful that this recommendation was followed or could be. Nor is the 
prescribed period adequate in view of the persistent nature of the residues. 
The Food and Drug Administration, although frowning on the presence of any pesticide 
residues in milk, has little authority in this situation. In most of the states included in the fire 
ant program the dairy industry is small and its products do not cross state lines. Protection of 
the milk supply endangered by a federal program is therefore left to the states themselves. 
Inquiries addressed to the health officers or other appropriate officials of Alabama, Louisiana, 
and Texas in 1959 revealed that no tests had been made and that it simply was not known 
whether the milk was contaminated with pesticides or not. 

Meanwhile, after rather than before the control program was launched, some research into the 
peculiar nature of heptachlor was done. Perhaps it would be more accurate to say that 
someone looked up the research already published, since the basic fact that brought about 
belated action by the federal government had been discovered several years before, and 
should have influenced the initial handling of the program. This is the fact that heptachlor, after 
a short period in the tissues of animals or plants or in the soil, assumes a considerably more 
toxic form known as heptachlor epoxide. The epoxide is popularly described as 'an oxidation 
product' produced by weathering. The fact that this transformation could occur had been 
known since 1952, when the Food and Drug Administration discovered that female rats, fed 30 
parts per million of heptachlor, had stored 165 parts per million of the more poisonous epoxide 
only 2 weeks later. These facts were allowed to come out of the obscurity of biological 
literature in 1959, when the Food and Drug Administration took action which had the effect of 
banning any residues of heptachlor or its epoxide on food. This ruling put at least a temporary 
damper on the program; although the Agriculture Department continued to press for its annual 
appropriations for fire ant control, local agricultural agents became increasingly reluctant to 
advise farmers to use chemicals which would probably result in their crops being legally 

In short, the Department of Agriculture embarked on its program without even elementary 
investigation of what was already known about the chemical to be used— or if it investigated, it 
ignored the findings. It must also have failed to do preliminary research to discover the 
minimum amount of the chemical that would accomplish its purpose. After three years of 

heavy dosages, it abruptly reduced the rate of application of heptachlor from 2 pounds to 1% 
pounds per acre in 1959; later on to Vi pound per acre, applied in two treatments of % pound 
each, 3 to 6 months apart. An official of the Department explained that 'an aggressive methods 
improvement program' showed the lower rate to be effective. Had this information been 
acquired before the program was launched, a vast amount of damage could have been avoided 
and the taxpayers could have been saved a great deal of money. In 1959, perhaps in an attempt 
to offset the growing dissatisfaction with the program, the Agriculture Department offered the 
chemicals free to Texas landowners who would sign a release absolving federal, state, and local 
governments of responsibility for da mage. In the same year the State of Alabama, alarmed and 
angry at the damage done by the chemicals, refused to appropriate any further funds for the 
project. One of its officials characterized the whole program as 'ill advised, hastily conceived, 
poorly planned, and a glaring example of riding roughshod over the responsibilities of other 
public and private agencies'. Despite the lack of state funds, federal money continued to trickle 
into Alabama, and in 1961 the legislature was again persuaded to make a small appropriation. 
Meanwhile, farmers in Louisiana showed growing reluctance to sign up for the project as it 
became evident that use of chemicals against the fire ant was causing an upsurge of insects 
destructive to sugarcane. Moreover, the program was obviously accomplishing nothing. Its 
dismal state was tersely summarized in the spring of 1962 by the director of entomology 
research at Louisiana State University Agricultural Experiment Station, Dr. L. D. Newsom: 'The 
imported fire ant "eradication" program which has been conducted by state and federal 
agencies is thus far a failure. There are more infested acres in Louisiana now than when the 
program began.' 

A swing to more sane and conservative methods seems to have begun. Florida, reporting that 
'there are more fire ants in Florida now than there were when the program started,' announced 
it was abandoning any idea of a broad eradication program and would instead concentrate on 
local control. Effective and inexpensive methods of local control have been known for years. 
The mound-building habit of the fire ant makes the chemical treatment of individual mounds a 
simple matter. Cost of such treatment is about one dollar per acre. For situations where 
mounds are numerous and mechanized methods are desirable, a cultivator which first levels 
and then applies chemical directly to the mounds has been developed by Mississippi's 
Agricultural Experiment Station. The method gives 90 to 95 per cent control of the ants. Its cost 
is only $0.23 per acre. The Agriculture Department's mass control program, on the other hand, 
cost about $3.50 per acre— the most expensive, the most damaging, and the least effective 
program of all. 

11. Beyond the Dreams of the Borgias 

THE CONTAMINATION of our world is not alone a matter of mass spraying. Indeed, for 
most of us this is of less importance than the innumerable small-scale exposures to which we 
are subjected day by day, year after year. Like the constant dripping of water that in turn wears 
away the hardest stone, this birth-to-death contact with dangerous chemicals may in the end 
prove disastrous. Each of these recurrent exposures, no matter how slight, contributes to the 
progressive buildup of chemicals in our bodies and so to cumulative poisoning. Probably no 
person is immune to contact with this spreading contamination unless he lives in the most 
isolated situation imaginable. Lulled by the soft sell and the hidden persuader, the average 
citizen is seldom aware of the deadly materials with which he is surrounding himself: indeed, he 
may not realize he is using them at all. So thoroughly has the age of poisons become 
established that anyone may walk into a store and, without questions being asked, buy 
substances of far greater death-dealing power than the medicinal drug for which he may be 
required to sign a 'poison book' in the pharmacy next door. A few minutes' research in any 
supermarket is enough to alarm the most stouthearted customer— provided, that is, he has 
even a rudimentary knowledge of the chemicals presented for his choice. 
If a huge skull and crossbones were suspended above the insecticide department the customer 
might at least enter it with the respect normally accorded death-dealing materials. But instead 
the display is homey and cheerful, and, with the pickles and olives across the aisle and the bath 
and laundry soaps adjoining, the rows upon rows of insecticides are displayed. Within easy 
reach of a child's exploring hand are chemicals in glass containers. If dropped to the floor by a 
child or careless adult everyone nearby could be splashed with the same chemical that has sent 
spraymen using it into convulsions. These hazards of course follow the purchaser right into his 
home. A can of a mothproofing material containing , for example, carries in very fine print the 
warning that its contents are under pressure and that it may burst if exposed to heat or open 
flame. A common insecticide for household use, including assorted uses in the kitchen, is 
chlordane. Yet the Food and Drug Administration's chief pharmacologist has declared the 
hazard of living in a house sprayed with chlordane to be 'very great'. Other household 
preparations contain the even more toxic dieldrin. 

Use of poisons in the kitchen is made both attractive and easy. Kitchen shelf paper, white or 
tinted to match one's color scheme, may be impregnated with insecticide, not merely on one 
but on both sides. Manufacturers offer us do-it-yourself booklets on how to kill bugs. With 
push-button ease, one may send a fog of dieldrin into the most inaccessible nooks and crannies 
of cabinets, corners, and baseboards. If we are troubled by mosquitoes, chiggers, or other 
insect pests on our persons we have a choice of innumerable lotions, creams, and sprays for 
application to clothing or skin. Although we are warned that some of these will dissolve varnish, 
paint, and synthetic fabrics, we are presumably to infer that the human skin is impervious to 
chemicals. To make certain that we shall at all times be prepared to repel insects, an exclusive 
New York store advertises a pocket-sized insecticide dispenser, suitable for the purse or for 
beach, golf, or fishing gear. 

We can polish our floors with a wax guaranteed to kill any insect that walks over it. We can 
hang strips impregnated with the chemical lindane in our closets and garment bags or place 

them in our bureau drawers for a half year's freedom from worry over moth damage. The 
advertisements contain no suggestion that lindane is dangerous. Neither do the ads for an 
electronic device that dispenses lindane fumes— we are told that it is safe and odorless. Yet the 
truth of the matter is that the American Medical Association considers lindane vaporizers so 
dangerous that it conducted an extended campaign against them in its Journal. 
The Department of Agriculture, in a Home and Garden Bulletin, advises us to spray our clothing 
with oil solutions of DDT, dieldrin, chlordane, or any of several other moth killers. If excessive 
spraying results in a white deposit of insecticide on the fabric, this may be removed by 
brushing, the Department says, omitting to caution us to be careful where and how the 
brushing is done. All these matters attended to, we may round out our day with insecticides by 
going to sleep under a mothproof blanket impregnated with dieldrin. Gardening is now firmly 
linked with the super poisons. Every hardware store, garden-supply shop, and supermarket has 
rows of insecticides for every conceivable horticultural situation. Those who fail to make wide 
use of this array of lethal sprays and dusts are by implication remiss, for almost every 
newspaper's garden page and the majority of the gardening magazines take their use for 
granted. So extensively are even the rapidly lethal organic phosphorus insecticides applied to 
lawns and ornamental plants that in 1960 the Florida State Board of Health found it necessary 
to forbid the commercial use of pesticides in residential areas by anyone who had not first 
obtained a permit and met certain requirements. A number of deaths from parathion had 
occurred in Florida before this regulation was adopted. 

Little is done, however, to warn the gardener or homeowner that he is handling extremely 
dangerous materials. On the contrary, a constant stream of new gadgets make it easier to use 
poisons on lawn and garden— and increase the gardener's contact with them. One may get a 
jar-type attachment for the garden hose, for example, by which such extremely dangerous 
chemicals as chlordane or dieldrin are applied as one waters the lawn. Such a device is not only 
a hazard to the person using the hose, it is also a public menace. The New York Times found it 
necessary to issue a warning on its garden page to the effect that unless special protective 
devices were installed poisons might get to the water supply by back siphonage. Considering 
the number of such devices that are in use, and the scarcity of warnings such as this, do we 
need to wonder why our public waters are contaminated? 

As an example of what may happen to the gardener himself, we might look at the case of a 
physician— an enthusiastic sparetime gardener— who began using DDT and then malathion on 
his shrubs and lawn, making regular weekly applications. Sometimes he applied the chemicals 
with a hand spray, sometimes with an attachment to his hose. In doing so, his skin and clothing 
were often soaked with spray. After about a year of this sort of thing, he suddenly collapsed 
and was hospitalized. Examination of a biopsy specimen of fat showed an accumulation of 23 
parts per million of DDT. There was extensive nerve damage, which his physicians regarded as 
permanent. As time went on he lost weight, suffered extreme fatigue, and experienced a 
peculiar muscular weakness, a characteristic effect of malathion. All of these persisting effects 
were severe enough to make it difficult for the physician to carry on his practice. Besides the 
once innocuous garden hose, power mowers also have been fitted with devices for the 
dissemination of pesticides, attachments that will dispense a cloud of vapor as the homeowner 
goes about the task of mowing his lawn. So to the potentially dangerous fumes from gasoline 

are added the finely divided particles of whatever insecticide the probably unsuspecting 
suburbanite has chosen to distribute, raising the level of air pollution above his own grounds to 
something few cities could equal. Yet little is said about the hazards of the fad of gardening by 
poisons, or of insecticides used in the home; warnings on labels are printed so inconspicuously 
in small type that few take the trouble to read or follow them. An industrial firm recently 
undertook to find out just how few. Its survey indicated that fewer than fifteen people out of a 
hundred of those using insecticide aerosols and sprays are even aware of the warnings on the 

The mores of suburbia now dictate that crabgrass must go at whatever cost. Sacks containing 
chemicals designed to rid the lawn of such despised vegetation have become almost a status 
symbol. These weed-killing chemicals are sold under brand names that never suggest their 
identity or nature. To learn that they contain chlordane or dieldrin one must read exceedingly 
fine print placed on the least conspicuous part of the sack. The descriptive literature that may 
be picked up in any hardware or garden-supply store seldom if ever reveals the true hazard 
involved in handling or applying the material. Instead, the typical illustration portrays a happy 
family scene, father and son smilingly preparing to apply the chemical to the lawn, small 
children tumbling over the grass with a dog. . . . 

The question of chemical residues on the food we eat is a hotly debated issue. The existence of 
such residues is either played down by the industry as unimportant or is flatly denied. 
Simultaneously, there is a strong tendency to brand as fanatics or cultists all who are so 
perverse as to demand that their food be free of insect poisons. In all this cloud of controversy, 
what are the actual facts? It has been medically established that, as common sense would tell 
us, persons who lived and died before the dawn of the DDT era (about 1942) contained no trace 
of DDT or any similar material in their tissues. As mentioned in Chapter 3, samples of body fat 
collected from the general population between 1954 and 1956 averaged from 5.3 to 7.4 parts 
per million of DDT. There is some evidence that the average level has risen since then to a 
consistently higher figure, and individuals with occupational or other special exposures to 
insecticides of course store even more. Among the general population with no known gross 
exposures to insecticides it may be assumed that much of the DDT stored in fat deposits has 
entered the body in food. To test this assumption, a scientific team from the United States 
Public Health Service sampled restaurant and institutional meals. Every meal sampled 
contained DDT. From this the investigators concluded reasonably enough, that 'few if any foods 
can be relied upon to be entirely free of DDT.' The quantities in such meals may be enormous. 
In a separate Public Health Service study, analysis of prison meals disclosed such items as 
stewed dried fruit containing 69.6 parts per million and bread containing 100.9 parts per million 
of DDT! In the diet of the average home, meats and any products derived from animal fats 
contain the heaviest residues of chlorinated hydrocarbons. This is because these chemicals are 
soluble in fat. Residues on fruits and vegetables tend to be somewhat less. These are little 
affected by washing— the only remedy is to remove and discard all outside leaves of such 
vegetables as lettuce or cabbage, to peel fruit and to use no skins or outer covering whatever. 
Cooking does not destroy residues. 

Milk is one of the few foods in which no pesticide residues are permitted by Food and Drug 
Administration regulations. In actual fact, however, residues turn up whenever a check is made. 
They are heaviest in butter and other manufactured dairy products. A check of 461 samples of 

such products in 1960 showed that a third contained residues, a situation which the Food and 
Drug Administration characterized as 'far from encouraging'. To find a diet free from DDT and 
related chemicals, it seems one must go to a remote and primitive land, still lacking the 
amenities of civilization. Such a land appears to exist, at least marginally, on the far Arctic 
shores of Alaska— although even there one may see the approaching shadow. When scientists 
investigated the native diet of the Eskimos in this region it was found to be free from 
insecticides. The fresh and dried fish; the fat, oil, or meat from beaver, beluga, caribou, moose, 
oogruk, polar bear, and walrus; cranberries, salmonberries and wild rhubarb all had so far 
escaped contamination. There was only one exception— two white owls from Point Hope 
carried small amounts of DDT, perhaps acquired in the course of some migratory journey. 
When some of the Eskimos themselves were checked by analysis of fat samples, small residues 
of DDT were found (0 to 1.9 parts per million). The reason for this was clear. The fat samples 
were taken from people who had left their native villages to enter the United States Public 
Health Service Hospital in Anchorage for surgery. There the ways of civilization prevailed, and 
the meals in this hospital were found to contain as much DDT as those in the most populous 
city. For their brief stay in civilization the Eskimos were rewarded with a taint of poison. The 
fact that every meal we eat carries its load of chlorinated hydrocarbons is the inevitable 
consequence of the almost universal spraying or dusting of agricultural crops with these 
poisons. If the farmer scrupulously follows the instructions on the labels, his use of agricultural 
chemicals will produce no residues larger than are permitted by the Food and Drug 
Administration. Leaving aside for the moment the question whether these legal residues are as 
'safe' as they are represented to be, there remains the well-known fact that farmers very 
frequently exceed the prescribed dosages, use the chemical too close to the time of harvest, 
use several insecticides where one would do, and in other ways display the common human 
failure to read the fine print. 

Even the chemical industry recognizes the frequent misuse of insecticides and the need for 
education of farmers. One of its leading trade journals recently declared that 'many users do 
not seem to understand that they may exceed insecticide tolerances if they use higher dosages 
than recommended. And haphazard use of insecticides on many crops may be based on 
farmers' whims.' The files of the Food and Drug Administration contain records of a disturbing 
number of such violations. A few examples will serve to illustrate the disregard of directions: a 
lettuce farmer who applied not one but eight different insecticides to his crop within a short 
time of harvest, a shipper who had used the deadly parathion on celery in an amount five times 
the recommended maximum, growers using endrin— most toxic of all the chlorinated 
hydrocarbons— on lettuce although no residue was allowable, spinach sprayed with DDT a 
week before harvest. There are also cases of chance or accidental contamination. Large lots of 
green coffee in burlap bags have become contaminated while being transported by vessels also 
carrying a cargo of insecticides. Packaged foods in warehouses are subjected to repeated 
aerosol treatments with DDT, lindane, and other insecticides, which may penetrate the 
packaging materials and occur in measurable quantities on the contained foods. The longer the 
food remains in storage, the greater the danger of contamination. 

To the question 'But doesn't the government protect us from such things?' the answer is, 'Only 
to a limited extent.' The activities of the Food and Drug Administration in the field of consumer 
protection against pesticides are severely limited by two facts. The first is that it has jurisdiction 

only over foods shipped in interstate commerce; foods grown and marketed within a state are 
entirely outside its sphere of authority, no matter what the violation. The second and critically 
limiting fact is the small number of inspectors on its staff— fewer than 600 men for all its varied 
work. According to a Food and Drug official, only an infinitesimal part of the crop products 
moving in interstate commerce— far less than 1 per cent— can be checked with existing 
facilities, and this is not enough to have statistical significance. As for food produced and sold 
within a state, the situation is even worse, for most states have woefully inadequate laws in this 
field. The system by which the Food and Drug Administration establishes maximum permissible 
limits of contamination, called 'tolerances', has obvious defects. Under the conditions 
prevailing it provides mere paper security and promotes a completely unjustified impression 
that safe limits have been established and are being adhered to. As to the safety of allowing a 
sprinkling of poisons on our food— a little on this, a little on that— many people contend, with 
highly persuasive reasons, that no poison is safe or desirable on food. In setting a tolerance 
level the Food and Drug Administration reviews tests of the poison on laboratory animals and 
then establishes a maximum level of contamination that is much less than required to produce 
symptoms in the test animal. This system, which is supposed to ensure safety, ignores a 
number of important facts. A laboratory animal, living under controlled and highly artificial 
conditions, consuming a given amount of a specific chemical, is very different from a human 
being whose exposures to pesticides are not only multiple but for the most part unknown, 
unmeasurable, and uncontrollable. Even if 7 parts per million of DDT on the lettuce in his 
luncheon salad were 'safe', the meal includes other foods, each with allowable residues, and 
the pesticides on his food are, as we have seen, only a part, and possibly a small part, of his 
total exposure. This piling up of chemicals from many different sources creates a total exposure 
that cannot be measured. It is meaningless, therefore, to talk about the 'safety' of any specific 
amount of residue. 

And there are other defects. Tolerances have sometimes been established against the better 
judgment of Food and Drug Administration scientists, as in the case cited on page 175 ff., or 
they have been established on the basis of inadequate knowledge of the chemical concerned. 
Better information has led to later reduction or withdrawal of the tolerance, but only after the 
public has been exposed to admittedly dangerous levels of the chemical for months or years. 
This happened when heptachlor was given a tolerance that later had to be revoked. For some 
chemicals no practical field method of analysis exists before a chemical is registered for use. 
Inspectors are therefore frustrated in their search for residues. This difficulty greatly hampered 
the work on the 'cranberry chemical', aminotriazole. Analytical methods are lacking, too, for 
certain fungicides in common use for the treatment of seeds— seeds which if unused at the end 
of the planting season, may very well find their way into human food. 

In effect, then, to establish tolerances is to authorize conta mination of public food supplies with 
poisonous chemicals in order that the farmer and the processor may enjoy the benefit of 
cheaper production— then to penalize the consumer by taxing him to maintain a policing 
agency to make certain that he shall not get a lethal dose. But to do the policing job properly 
would cost money beyond any legislator's courage to appropriate, given the present volume 
and toxicity of agricultural chemicals. So in the end the luckless consumer pays his taxes but 
gets his poisons regardless. What is the solution? The first necessity is the elimination of 
tolerances on the chlorinated hydrocarbons, the organic phosphorus group, and other highly 

toxic chemicals. It will immediately be objected that this will place an intolerable burden on the 
farmer. But if, as is now the presumable goal, it is possible to use chemicals in such a way that 
they leave a residue of only 7 parts per million (the tolerance for DDT), or of 1 part per million 
(the tolerance for parathion), or even of only 0.1 part per million as is required for dieldrin on a 
great variety of fruits and vegetables, then why is it not possible, with only a little more care, to 
prevent the occurrence of any residues at all? This, in fact, is what is required for some 
chemicals such as heptachlor, endrin, and dieldrin on certain crops. If it is considered practical 
in these instances, why not for all? 

But this is not a complete or final solution, for a zero tolerance on paper is of little value. At 
present, as we have seen, more than 99 per cent of the interstate food shipments slip by 
without inspection. A vigilant and aggressive Food and Drug Administration, with a greatly 
increased force of inspectors, is another urgent need. This system, however— deliberately 
poisoning our food, then policing the result— is too reminiscent of Lewis Carroll's White Knight 
who thought of 'a plan to dye one's whiskers green, and always use so large a fan that they 
could not be seen.' The ultimate answer is to use less toxic chemicals so that the public hazard 
from their misuse is greatly reduced. Such chemicals already exist: the pyrethrins, rotenone, 
ryania, and others derived from plant substances. Synthetic substitutes for the pyrethrins have 
recently been developed, and some of the producing countries stand ready to increase the 
output of the natural product as the market may require. Public education as to the nature of 
the chemicals offered for sale is sadly needed. The average purchaser is completely bewildered 
by the array of available insecticides, fungicides, and weed killers, and has no way of knowing 
which are the deadly ones, which reasonably safe. 

In addition to making this change to less dangerous agricultural pesticides, we should diligently 
explore the possibilities of nonchemical methods. Agricultural use of insect diseases, caused by 
a bacterium highly specific for certain types of insects, is already being tried in California, and 
more extended tests of this method are under way. A great many other possibilities exist for 
effective insect control by methods that will leave no residues on foods (see Chapter 17). Until a 
large-scale conversion to these methods has been made, we shall have little relief from a 
situation that, by any commonsense standards, is intolerable. As matters stand now, we are in 
little better position than the guests of the Borgias. 

12. The Human Price 

AS THE TIDE of chemicals bom of the Industrial Age has arisen to engulf our 
environment, a drastic change has come about in the nature of the most serious public health 
problems. Only yesterday mankind lived in fear of the scourges of smallpox, cholera, and plague 
that once swept nations before them. Now our major concern is no longer with the disease 
organisms that once were omnipresent; sanitation, better living conditions, and new drugs 
have given us a high degree of control over infectious disease. Today we are concerned with a 
different kind of hazard that lurks in our environment— a hazard we ourselves have introduced 
into our world as our modern way of life has evolved. 

The new environmental health problems are multiple— created by radiation in all its forms, 
born of the never-ending stream of chemicals of which pesticides are a part, chemicals now 
pervading the world in which we live, acting upon us directly and indirectly, separately and 
collectively. Their presence casts a shadow that is no less ominous because it is formless and 
obscure, no less frightening because it is simply impossible to predict the effects of lifetime 
exposure to chemical and physical agents that are not part of the biological experience of man. 
'We all live under the haunting fear that something may corrupt the environment to the point 
where man joins the dinosaurs as an obsolete form of life,' says Dr. David Price of the United 
States Public Health Service. 'And what makes these thoughts all the more disturbing is the 
knowledge that our fate could perhaps be sealed twenty or more years before the 
development of symptoms.' Where do pesticides fit into the picture of environmental disease? 
We have seen that they now contaminate soil, water, and food, that they have the power to 
make our streams fishless and our gardens and woodlands silent and birdless. Man, however 
much he may like to pretend the contrary, is part of nature. Can he escape a pollution that is 
now so thoroughly distributed throughout our world? 

We know that even single exposures to these chemicals, if the amount is large enough, can 
precipitate acute poisoning. But this is not the major problem. The sudden illness or death of 
farmers, spraymen, pilots, and others exposed to appreciable quantities of pesticides are tragic 
and should not occur. For the population as a whole, we must be more concerned with the 
delayed effects of absorbing small amounts of the pesticides that invisibly contaminate our 
world. Responsible public health officials have pointed out that the biological effects of 
chemicals are cumulative over long periods of time, and that the hazard to the individual may 
depend on the sum of the exposures received throughout his lifetime. For these very reasons 
the danger is easily ignored. It is human nature to shrug off what may seem to us a vague threat 
of future disaster. 'Men are naturally most impressed by diseases which have obvious 
manifestations,' says a wise physician, Dr. Rene Dubos, 'yet some of their worst enemies creep 
on them unobtrusively.' For each of us, as for the robin in Michigan or the salmon in the 
Miramichi, this is a problem of ecology, of interrelationships, of interdependence. We poison 
the caddis flies in a stream and the salmon runs dwindle and die. We poison the gnats in a lake 
and the poison travels from link to link of the food chain and soon the birds of the lake margins 
become its victims. We spray our elms and the following springs are silent of robin song, not 
because we sprayed the robins directly but because the poison traveled, step by step, through 
the now familiar elm leaf-earthworm-robin cycle. These are matters of record, observable, part 

of the visible world around us. They reflect the web of life— or death— that scientists know as 

But there is also an ecology of the world within our bodies. In this unseen world minute causes 
produce mighty effects; the effect, moreover, is often seemingly unrelated to the cause, 
appearing in a part of the body remote from the area where the original injury was sustained. 
'A change at one point, in one molecule even, may reverberate throughout the entire system to 
initiate changes in seemingly unrelated organs and tissues,' says a recent summary of the 
present status of medical research. When one is concerned with the mysterious and wonderful 
functioning of the human body, cause and effect are seldom simple and easily demonstrated 
relationships. They may be widely separated both in space and time. To discover the agent of 
disease and death depends on a patient piecing together of many seemingly distinct and 
unrelated facts developed through a vast amount of research in widely separated fields. 
We are accustomed to look for the gross and immediate effect and to ignore all else. Unless this 
appears promptly and in such obvious form that it cannot be ignored, we deny the existence of 
hazard. Even research men suffer from the handicap of inadequate methods of detecting the 
beginnings of injury. The lack of sufficiently delicate methods to detect injury before symptoms 
appear is one of the great unsolved problems in medicine. 

'But,' someone will object, 'I have used dieldrin sprays on the lawn many times but I have never 
had convulsions like the World Health Organization spraymen— so it hasn't harmed me.' It is 
not that simple. Despite the absence of sudden and dra matic symptoms, one who handles such 
materials is unquestionably storing up toxic materials in his body. Storage of the chlorinated 
hydrocarbons, as we have seen, is cumulative, beginning with the smallest intake. The toxic 
materials become lodged in all the fatty tissues of the body. When these reserves of fat are 
drawn upon, the poison may then strike quickly. A New Zealand medical journal recently 
provided an example. A man under treatment for obesity suddenly developed symptoms of 
poisoning. On examination his fat was found to contain stored dieldrin, which had been 
metabolised as he lost weight. The same thing could happen with loss of weight in illness. 
The results of storage, on the other hand, could be even less obvious. Several years ago the 
Journal of the American Medical Association warned strongly of the hazards of insecticide 
storage in adipose tissue, pointing out that drugs or chemicals that are cumulative require 
greater caution than those having no tendency to be stored in the tissues. The adipose tissue, 
we are warned, is not merely a place for the deposition of fat (which makes up about 18 per 
cent of the body weight), but has many important functions with which the stored poisons may 
interfere. Furthermore, fats are very widely distributed in the organs and tissues of the whole 
body, even being constituents of cell membranes. It is important to remember, therefore, that 
the fat-soluble insecticides become stored in individual cells, where they are in position to 
interfere with the most vital and necessary functions of oxidation and energy production. This 
important aspect of the problem will be taken up in the next chapter. 

One of the most significant facts about the chlorinated hydrocarbon insecticides is their effect 
on the liver. Of all organs in the body the liver is most extraordinary. In its versatility and in the 
indispensable nature of its functions it has no equal. It presides over so many vital activities that 
even the slightest damage to it is fraught with serious consequences. Not only does it provide 
bile for the digestion of fats, but because of its location and the special circulatory pathways 
that converge upon it, the liver receives blood directly from the digestive tract and is deeply 

involved in the metabolism of all the principal foodstuffs. It stores sugar in the form of glycogen 
and releases it as glucose in carefully measured quantities to keep the blood sugar at a normal 
level. It builds body proteins, including some essential elements of blood plasma concerned 
with blood-clotting. It maintains cholesterol at its proper level in the blood plasma, and 
inactivates the male and female hormones when they reach excessive levels. It is a storehouse 
of many vitamins, some of which in turn contribute to its own proper functioning. 
Without a normally functioning liver the body would be disarmed— defenceless against the 
great variety of poisons that continually invade it. Some of these are normal by-products of 
metabolism, which the liver swiftly and efficiently makes harmless by withdrawing their 
nitrogen. But poisons that have no normal place in the body may also be detoxified. The 
'harmless' insecticides malathion and methoxychlor are less poisonous than their relatives only 
because a liver enzyme deals with them, altering their molecules in such a way that their 
capacity for harm is lessened. In similar ways the liver deals with the majority of the toxic 
materials to which we are exposed. 

Our line of defense against invading poisons or poisons from within is now weakened and 
crumbling. A liver damaged by pesticides is not only incapable of protecting us from poisons, 
the whole wide range of its activities may be interfered with. Not only are the consequences 
far-reaching, but because of their variety and the fact that they may not immediately appear 
they may not be attributed to their true cause. In connection with the nearly universal use of 
insecticides that are liver poisons, it is interesting to note the sharp rise in hepatitis that began 
during the 1950s and is continuing a fluctuating climb. Cirrhosis also is said to be increasing. 
While it is admittedly difficult, in dealing with human beings rather than laboratory animals, to 
'prove' that cause A produces effect B, plain common sense suggests that the relation between 
a soaring rate of liver disease and the prevalence of liver poisons in the environment is no 
coincidence. Whether or not the chlorinated hydrocarbons are the primary cause, it seems 
hardly sensible under the circumstances to expose ourselves to poisons that have a proven 
ability to damage the liver and so presumably to make it less resistant to disease. 
Both major types of insecticides, the chlorinated hydrocarbons and the organic phosphates, 
directly affect the nervous system, although in somewhat different ways. This has been made 
clear by an infinite number of experiments on animals and by observations on human subjects 
as well. As for DDT, the first of the new organic insecticides to be widely used, its action is 
primarily on the central nervous system of man; the cerebellum and the higher motor cortex 
are thought to be the areas chiefly affected. Abnormal sensations as of prickling, burning, or 
itching, as well as tremors or even convulsions may follow exposure to appreciable amounts, 
according to a standard textbook of toxicology. 

Our first knowledge of the symptoms of acute poisoning by DDT was furnished by several 
British investigators, who deliberately exposed themselves in order to learn the consequences. 
Two scientists at the British Royal Navy Physiological Laboratory invited absorption of DDT 
through the skin by direct contact with walls covered with a water soluble paint containing 2 
per cent DDT, overlaid with a thin film of oil. The direct effect on the nervous system is 
apparent in their eloquent description of their symptoms: 'The tiredness, heaviness, and aching 
of limbs were very real things, and the mental state was also most distressing. ..[there was] 
extreme irritability.. .great distaste for work of any sort. ..a feeling of mental incompetence in 
tackling the simplest mental task. The joint pains were quite violent at times.' 

Another British experimenter who applied DDT in acetone solution to his skin reported 
heaviness and aching of limbs, muscular weakness, and 'spasms of extreme nervous tension'. 
He took a holiday and improved, but on return to work his condition deteriorated. He then 
spent three weeks in bed, made miserable by constant aching in limbs, insomnia, nervous 
tension, and feelings of acute anxiety. On occasion tremors shook his whole body— tremors of 
the sort now made all too familiar by the sight of birds poisoned by DDT. The experimenter lost 
10 weeks from his work, and at the end of a year, when his case was reported in a British 
medical journal, recovery was not complete. (Despite this evidence, several American 
investigators conducting an experiment with DDT on volunteer subjects dismissed the 
complaint of headache and 'pain in every bone' as 'obviously of psychoneurotic origin'.) 
There are now many cases on record in which both the symptoms and the whole course of the 
illness point to insecticides as the cause. Typically, such a victim has had a known exposure to 
one of the insecticides, his symptoms have subsided under treatment which included the 
exclusion of all insecticides from his environment, and most significantly have returned with 
each renewed contact with the offending chemicals. This sort of evidence— and no more- 
forms the basis of a vast amount of medical therapy in many other disorders. There is no 
reason why it should not serve as a warning that it is no longer sensible to take the 'calculated 
risk' of saturating our environment with pesticides. Why does not everyone handling and using 
insecticides develop the same symptoms? Here the matter of individual sensitivity enters in. 
There is some evidence that women are more susceptible than men, the very young more than 
adults, those who lead sedentary, indoor lives more than those leading a rugged life of work or 
exercise in the open. Beyond these differences are others that are no less real because they are 
intangible. What makes one person allergic to dust or pollen, sensitive to a poison, or 
susceptible to an infection whereas another is not is a medical mystery for which there is at 
present no explanation. The problem nevertheless exists and it affects significant numbers of 
the population. Some physicians estimate that a third or more of their patients show signs of 
some form of sensitivity, and that the number is growing. And unfortunately, sensitivity may 
suddenly develop in a person previously insensitive. In fact, some medical men believe that 
intermittent exposures to chemicals may produce just such sensitivity. If this is true, it may 
explain why some studies on men subjected to continuous occupational exposure find little 
evidence of toxic effects. By their constant contact with the chemicals these men keep 
themselves desensitized— as an allergist keeps his patients desensitized by repeated small 
injections of the allergen. The whole problem of pesticide poisoning is enormously complicated 
by the fact that a human being, unlike a laboratory animal living under rigidly controlled 
conditions, is never exposed to one chemical alone. Between the major groups of insecticides, 
and between them and other chemicals, there are interactions that have serious potentials. 
Whether released into soil or water or a man's blood, these unrelated chemicals do not remain 
segregated; there are mysterious and unseen changes by which one alters the power of 
another for harm. There is interaction even between the two major groups of insecticides 
usually thought to be completely distinct in their action. The power of the organic phosphates, 
those poisoners of the nerve-protective enzyme cholinesterase, may become greater if the 
body has first been exposed to a chlorinated hydrocarbon which injures the liver. This is 
because, when liver function is disturbed, the cholinesterase level drops below normal. The 
added depressive effect of the organic phosphate may then be enough to precipitate acute 

symptoms. And as we have seen, pairs of the organic phosphates themselves may interact in 
such a wayas to increase theirtoxicity a hundredfold. Orthe organic phosphates may interact 
with various drugs, or with synthetic materials, food additives— who can say what else of the 
infinite number of manmade substances that now pervade our world? 

The effect of a chemical of supposedly innocuous nature can be drastically changed by the 
action of another; one of the best examples is a close relative of DDT called methoxychlor. 
(Actually, methoxychlor may not be as free from dangerous qualities as it is generally said to be, 
for recent work on experimental animals shows a direct action on the uterus and a blocking 
effect on some of the powerful pituitary hormones— reminding us again that these are 
chemicals with enormous biologic effect. Other work shows that methoxychlor has a potential 
ability to damage the kidneys.) Because it is not stored to any great extent when given alone, 
we are told that methoxychlor is a safe chemical. But this is not necessarily true. If the liver has 
been damaged by another agent, methoxychlor is stored in the body at 100 times its normal 
rate, and will then imitate the effects of DDT with long-lasting effects on the nervous system. 
Yet the liver damage that brings this about might be so slight as to pass unnoticed. It might 
have been the result of any of a number of commonplace situations— using another insecticide, 
using a cleaning fluid containing carbon tetrachloride, or taking one of the so-called 
tranquilizing drugs, a number (but not all) of which are chlorinated hydrocarbons and possess 
power to damage the liver. 

Damage to the nervous system is not confined to acute poisoning; there may also be delayed 
effects from exposure. Long-lasting damage to brain or nerves has been reported for 
methoxychlor and others. Dieldrin, besides its immediate consequences, can have long delayed 
effects ranging from 'loss of memory, insomnia, and nightmares to mania'. Lindane, according 
to medical findings, is stored in significant amounts in the brain and functioning liver tissue and 
may induce 'profound and long lasting effects on the central nervous system'. Yet this chemical, 
a form of benzene hexachloride, is much used in vaporizers, devices that pour a stream of 
volatilized insecticide vapor into homes, offices, restaurants. The organic phosphates, usually 
considered only in relation to their more violent manifestations in acute poisoning, also have 
the power to produce lasting physical damage to nerve tissues and, according to recent 
findings, to induce mental disorders. Various cases of delayed paralysis have followed use of 
one or another of these insecticides. A bizarre happening in the United States during the 
prohibition era about 1930 was an omen of things to come. It was caused not by an insecticide 
but by a substance belonging chemically to the same group as the organic phosphate 
insecticides. During that period some medicinal substances were being pressed into service as 
substitutes for liquor, being exempt from the prohibition law. One of these was Jamaica ginger. 
But the United States Pharmacopeia product was expensive, and bootleggers conceived the 
idea of making a substitute Jamaica ginger. They succeeded so well that their spurious product 
responded to the appropriate chemical tests and deceived the government chemists. To give 
their false ginger the necessary tang they had introduced a chemical known as triorthocresyl 
phosphate. This chemical, like parathion and its relatives, destroys the protective enzyme 
cholinesterase. As a consequence of drinking the bootleggers' product some 15,000 people 
developed a permanently crippling type of paralysis of the leg muscles, a condition now called 
'ginger paralysis'. The paralysis was accompanied by destruction of the nerve sheaths and by 
degeneration of the cells of the anterior horns of the spinal cord. 

About two decades later various other organic phosphates came into use as insecticides, as we 
have seen, and soon cases reminiscent of the ginger paralysis episode began to occur. One was 
a greenhouse worker in Germany who became paralyzed several months after experiencing 
mild symptoms of poisoning on a few occasions after using parathion. Then a group of three 
chemical plant workers developed acute poisoning from exposure to other insecticides of this 
group. They recovered under treatment, but ten days later two of them developed muscular 
weakness in the legs. This persisted for 10 months in one; the other, a young woman chemist, 
was more severely affected, with paralysis in both legs and some involvement of the hands and 
arms. Two years later when her case was reported in a medical journal she was still unable to 
walk. The insecticide responsible for these cases has been withdrawn from the market, but 
some of those now in use may be capable of like harm. Malathion (beloved of gardeners) has 
induced severe muscular weakness in experiments on chickens. This was attended (as in ginger 
paralysis) by destruction of the sheaths of the sciatic and spinal nerves. All these consequences 
of organic phosphate poisoning, if survived, may be a prelude to worse. In view of the severe 
damage they inflict upon the nervous system, it was perhaps inevitable that these insecticides 
would eventually be linked with mental disease. That link has recently been supplied by 
investigators at the University of Melbourne and Prince Henry's Hospital in Melbourne, who 
reported on 16 cases of mental disease. All had a history of prolonged exposure to organic 
phosphorus insecticides. Three were scientists checking the efficacy of sprays; 8 worked in 
greenhouses; 5 were farm workers. Their symptoms ranged from impairment of memory to 
schizophrenic and depressive reactions. All had normal medical histories before the chemicals 
they were using boome ranged and struck them down. 

Echoes of this sort of thing are to be found, as we have seen, widely scattered throughout 
medical literature, sometimes involving the chlorinated hydrocarbons, sometimes the organic 
phosphates. Confusion, delusions, loss of memory, mania— a heavy price to pay for the 
temporary destruction of a few insects, but a price that will continue to be exacted as long as 
we insist upon using chemicals that strike directly at the nervous system. 

13. Through a Narrow Window 

THE BIOLOGIST George Wald once compared his work on an exceedingly specialized 
subject, the visual pigments of the eye, to 'a very narrow window through which at a distance 
one can see only a crack of light. As one comes closer the view grows wider and wider, until 
finally through this same narrow window one is looking at the universe.' So it is that only when 
we bring our focus to bear, first on the individual cells of the body, then on the minute 
structures within the cells, and finally on the ultimate reactions of molecules within these 
structures— only when we do this can we comprehend the most serious and far-reaching 
effects of the haphazard introduction of foreign chemicals into our internal environment. 
Medical research has only rather recently turned to the functioning of the individual cell in 
producing the energy that is the indispensable quality of life. The extraordinary energy- 
producing mechanism of the body is basic not only to health but to life; it transcends in 
importance even the most vital organs, for without the smooth and effective functioning of 
energy-yielding oxidation none of the body's functions can be performed. Yet the nature of 
many of the chemicals used against insects, rodents, and weeds is such that they may strike 
directly at this system, disrupting its beautifully functioning mechanism. 

The research that led to our present understanding of cellular oxidation is one of the most 
impressive accomplishments in all biology and biochemistry. The roster of contributors to this 
work includes many Nobel Prize winners. Step by step it has been going on for a quarter of a 
century, drawing on even earlier work for some of its foundation stones. Even yet it is not 
complete in all details. And only within the past decade have all the varied pieces of research 
come to form a whole so that biological oxidation could become part of the common 
knowledge of biologists. Even more important is the fact that medical men who received their 
basic training before 1950 have had little opportunity to realize the critical importance of the 
process and the hazards of disrupting it. 

The ultimate work of energy production is accomplished not in any specialized organ but in 
every cell of the body. A living cell, like a flame, burns fuel to produce the energy on which life 
depends. The analogy is more poetic than precise, for the cell accomplishes its 'burning' with 
only the moderate heat of the body's normal temperature. Yet all these billions of gently 
burning little fires spark the energy of life. Should they cease to burn, 'no heart could beat, no 
plant could grow upward defying gravity, no amoeba could swim, no sensation could speed 
along a nerve, no thought could flash in the human brain,' said the chemist Eugene 

The transformation of matter into energy in the cell is an ever-flowing process, one of nature's 
cycles of renewal, like a wheel endlessly turning. Grain by grain, molecule by molecule, 
carbohydrate fuel in the form of glucose is fed into this wheel; in its cyclic passage the fuel 
molecule undergoes fragmentation and a series of minute chemical changes. The changes are 
made in orderly fashion, step by step, each step directed and controlled by an enzyme of so 
specialized a function that it does this one thing and nothing else. At each step energy is 
produced, waste products (carbon dioxide and water) are given off, and the altered molecule of 
fuel is passed on to the next stage. When the turning wheel comes full cycle the fuel molecule 

has been stripped down to a form in which it is ready to combine with a new molecule coming 
in and to start the cycle anew. 

This process by which the cell functions as a chemical factory is one of the wonders of the living 
world. The fact that all the functioning parts are of infinitesimal size adds to the miracle. With 
few exceptions cells themselves are minute, seen only with the aid of a microscope. Yet the 
greater part of the work of oxidation is performed in a theater far smaller, in tiny granules 
within the cell called mitochondria. Although known for more than 60 years, these were 
formerly dismissed as cellular elements of unknown and probably unimportant function. Only 
in the 1950s did their study become an exciting and fruitful field of research; suddenly they 
began to engage so much attention that 1000 papers on this subject alone appeared within a 
five-year period. Again one stands in awe at the marvelous ingenuity and patience by which the 
mystery of the mitochondria has been solved. Imagine a particle so small that you can barely 
see it even though a microscope has enlarged it for you 300 times. Then imagine the skill 
required to isolate this particle, to take it apart and analyze its components and determine their 
highly complex functioning. Yet this has been done with the aid of the electron microscope and 
the techniques of the biochemist. 

It is now known that the mitochondria are tiny packets of enzymes, a varied assortment 
including all the enzymes necessary for the oxidative cycle, arranged in precise and orderly 
array on walls and partitions. The mitochondria are the 'powerhouses' in which most of the 
energy-producing reactions occur. After the first, preliminary steps of oxidation have been 
performed in the cytoplasm the fuel molecule is taken into the mitochondria. It is here that 
oxidation is completed; it is here that enormous amounts of energy are released. The endlessly 
turning wheels of oxidation within the mitochondria would turn to little purpose if it were not 
for this all-important result. The energy produced at each stage of the oxidative cycle is in a 
form familiarly spoken of by the biochemists as ATP (adenosine triphosphate), a molecule 
containing three phosphate groups. The role of ATP in furnishing energy comes from the fact 
that it can transfer one of its phosphate groups to other substances, along with the energy of 
its bonds of electrons shuttling back and forth at high speed. Thus, in a muscle cell, energy to 
contract is gained when a terminal phosphate group is transferred to the contracting muscle. So 
another cycle takes place— a cycle within a cycle: a molecule of ATP gives up one of its 
phosphate groups and retains only two, becoming a diphosphate molecule, ADP. But as the 
wheel turns further another phosphate group is coupled on and the potent ATP is restored. The 
analogy of the storage battery has been used: ATP represents the charged, ADP the discharged 

ATP is the universal currency of energy— found in all organisms from microbes to man. It 
furnishes mechanical energy to muscle cells; electrical energy to nerve cells. The sperm cell, the 
fertilized egg ready for the enormous burst of activity that will transform it into a frog or a bird 
or a human infant, the cell that must create a hormone, all are supplied with ATP. Some of the 
energy of ATP is used in the mitochondrion but most of it is immediately dispatched into the 
cell to provide powerfor other activities. The location of the mitochondria within certain cells is 
eloquent of their function, since they are placed so that energy can be delivered precisely 
where it is needed. In muscle cells they cluster around contracting fibers; in nerve cells they are 
found at the junction with another cell, supplying energy for the transfer of impulses; in sperm 
cells they are concentrated at the point where the propellant tail is joined to the head. 

The charging of the battery, in which ADP and a free phosphate group are combined to restore 
ATP, is coupled to the oxidative process; the close linking is known as coupled phosphorylation. 
If the combination becomes uncoupled, the means is lost for providing usable energy. 
Respiration continues but no energy is produced. The cell has become like a racing engine, 
generating heat but yielding no power. Then the muscle cannot contract, nor can the impulse 
race along the nerve pathways. Then the sperm cannot move to its destination; the fertilized 
egg cannot carry to completion its complex divisions and elaborations. The consequences of 
uncoupling could indeed be disastrous for any organism from embryo to adult: in time it could 
lead to the death of the tissue or even of the organism. How can uncoupling be brought about? 
Radiation is an uncoupler, and the death of cells exposed to radiation is thought by some to be 
brought about in this way. Unfortunately, a good many chemicals also have the power to 
separate oxidation from energy production, and the insecticides and weed killers are well 
represented on the list. The phenols, as we have seen, have a strong effect on metabolism, 
causing a potentially fatal rise in temperature; this is brought about by the 'racing engine' effect 
of uncoupling. The dinitrophenols and pentachlorophenols are examples of this group that have 
widespread use as herbicides. Another uncoupler among the herbicides is 2,4-D. Of the 
chlorinated hydrocarbons, DDT is a proven uncoupler and further study will probably reveal 
others among this group. But uncoupling is not the only way to extinguish the little fires in 
some or all of the body's billions of cells. We have seen that each step in oxidation is directed 
and expedited by a specific enzyme. When any of these enzymes— even a single one of them— 
is destroyed or weakened, the cycle of oxidation within the cell comes to a halt. It makes no 
difference which enzyme is affected. Oxidation progresses in a cycle like a turning wheel. If we 
thrust a crowbar between the spokes of a wheel it makes no difference where we do it, the 
wheel stops turning. In the same way, if we destroy an enzyme that functions at any point in 
the cycle, oxidation ceases. There is then no further energy production, so the end effect is very 
similarto uncoupling. 

The crowbar to wreck the wheels of oxidation can be supplied by any of a number of chemicals 
commonly used as pesticides. DDT, methoxychlor, malathion, phenothiazine, and various 
dinitro compounds are among the numerous pesticides that have been found to inhibit one or 
more of the enzymes concerned in the cycle of oxidation. They thus appear as agents 
potentially capable of blocking the whole process of energy production and depriving the cells 
of utilizable oxygen. This is an injury with most disastrous consequences, only a few of which 
can be mentioned here. Merely by systematically withholding oxygen, experimenters have 
caused normal cells to turn into cancer cells, as we shall see in the following chapter. Some hint 
of other drastic consequences of depriving a cell of oxygen can be seen in animal experiments 
on developing embryos. With insufficient oxygen the orderly processes by which the tissues 
unfold and the organs develop are disrupted; malformations and other abnormalities then 
occur. Presumably the human embryo deprived of oxygen may also develop congenital 

There are signs that an increase in such disasters is being noticed, even though few look far 
enough to find all of the causes. In one of the more unpleasant portents of the times, the Office 
of Vital Statistics in 1961 initiated a national tabulation of malformations at birth, with the 
explanatory comment that the resulting statistics would provide needed facts on the incidence 
of congenital malformations and the circumstances under which they occur. Such studies will 

no doubt be directed largely toward measuring the effects of radiation, but it must not be 
overlooked that many chemicals are the partners of radiation, producing precisely the same 
effects. Some of the defects and malformations in tomorrow's children, grimly anticipated by 
the Office of Vital Statistics, will almost certainly be caused by these chemicals that permeate 
our outer and inner worlds. It may well be that some of the findings about diminished 
reproduction are also linked with interference with biological oxidation, and consequent 
depletion of the all-important storage batteries of ATP. The egg, even before fertilization, needs 
to be generously supplied with ATP, ready and waiting for the enormous effort, the vast 
expenditure of energy that will be required once the sperm has entered and fertilization has 
occurred. Whether the sperm cell will reach and penetrate the egg depends upon its own 
supply of ATP, generated in the mitochondria thickly clustered in the neck of the cell. Once 
fertilization is accomplished and cell division has begun, the supply of energy in the form of ATP 
will largely determine whether the development of the embryo will proceed to completion. 
Embryologists studying some of their most convenient subjects, the eggs of frogs and of sea 
urchins, have found that if the ATP content is reduced below a certain critical level the egg 
simply stops dividing and soon dies. 

It is not an impossible step from the embryology laboratory to the apple tree where a robin's 
nest holds its complement of blue-green eggs; but the eggs lie cold, the fires of life that 
flickered for a few days now extinguished. Or to the top of a tall Florida pine where a vast pile 
of twigs and sticks in ordered disorder holds three large white eggs, cold and lifeless. Why did 
the robins and the eaglets not hatch? Did the eggs of the birds, like those of the laboratory 
frogs, stop developing simply because they lacked enough of the common currency of energy— 
the ATP molecules— to complete their development? And was the lack of ATP brought about 
because in the body of the parent birds and in the eggs there were stored enough insecticides 
to stop the little turning wheels of oxidation on which the supply of energy depends? It is no 
longer necessary to guess about the storage of insecticides in the eggs of birds, which obviously 
lend themselves to this kind of observation more readily than the mammalian ovum. Large 
residues of DDT and other hydrocarbons have been found whenever looked for in the eggs of 
birds subjected to these chemicals, either experimentally or in the wild. And the concentrations 
have been heavy. Pheasant eggs in a California experiment contained up to 349 parts per 
million of DDT. In Michigan, eggs taken from the oviducts of robins dead of DDT poisoning 
showed concentrations up to 200 parts per million. Other eggs were taken from nests left 
unattended as parent robins were stricken with poison; these too contained DDT. Chickens 
poisoned by aldrin used on a neighboring farm have passed on the chemical to thei r eggs; hens 
experimentally fed DDT laid eggs containing as much as 65 parts per million. 
Knowing that DDT and other (perhaps all) chlorinated hydrocarbons stop the energy-producing 
cycle by inactivating a specific enzyme or uncoupling the energy-producing mechanism, it is 
hard to see how any egg so loaded with residues could complete the complex process of 
development: the infinite number of cell divisions, the elaboration of tissues and organs, the 
synthesis of vital substances that in the end produce a living creature. All this requires vast 
amounts of energy— the little packets of ATP which the turning of the metabolic wheel alone 
can produce. There is no reason to suppose these disastrous events are confined to birds. ATP 
is the universal currency of energy, and the metabolic cycles that produce it turn to the same 

purpose in birds and bacteria, in men and mice. The fact of insecticide storage in the germ cells 
of any species should therefore disturb us, suggesting comparable effects in human beings. 
And there are indications that these chemicals lodge in tissues concerned with the manufacture 
of germ cells as well as in the cells themselves. Accumulations of insecticides have been 
discovered in the sex organs of a variety of birds and mammals— in pheasants, mice, and guinea 
pigs under controlled conditions, in robins in an area sprayed for elm disease, and in deer 
roaming western forests sprayed for spruce budworm. In one of the robins the concentration of 
DDT in the testes was heavier than in any other part of the body. Pheasants also accumulated 
extraordinary amounts in the testes, up to 1500 parts per million. Probably as an effect of such 
storage in the sex organs, atrophy of the testes has been observed in experimental mammals. 
Young rats exposed to methoxychlor had extraordinarily small testes. When young roosters 
were fed DDT, the testes made only 18 per cent of their normal growth; combs and wattles, 
dependent for their development upon the testicular hormone, were only a third the normal 
size. The spermatozoa themselves may well be affected by loss of ATP. Experiments show that 
the motility of bull sperm is decreased by dinitrophenol, which interferes with the energy- 
coupling mechanism with inevitable loss of energy. The same effect would probably be found 
with other chemicals were the matter investigated. Some indication of the possible effect on 
human beings is seen in medical reports of oligospermia, or reduced production of 
spermatozoa, among aviation crop dusters applying DDT. . . . 

For mankind as a whole, a possession infinitely more valuable than individual life is our genetic 
heritage, our link with past and future. Shaped through long eons of evolution, our genes not 
only make us what we are, but hold in their minute beings the future— be it one of promise or 
threat. Yet genetic deterioration through man-made agents is the menace of our time, 'the last 
and greatest danger to our civilization'. Again the parallel between chemicals and radiation is 
exact and inescapable. The living cell assaulted by radiation suffers a variety of injuries: its 
ability to divide normally may be destroyed, it may suffer changes in chromosome structure, or 
the genes, carriers of hereditary material, may undergo those sudden changes known as 
mutations, which cause them to produce new characteristics in succeeding generations. If 
especially susceptible the cell may be killed outright, or finally, after the passage of time 
measured in years, it may become malignant. 

All these consequences of radiation have been duplicated in laboratory studies by a large group 
of chemicals known as radiomimetic or radiation-imitating. Many chemicals used as 
pesticides— herbicides as well as insecticides— belong to this group of substances that have the 
ability to damage the chromosomes, interfere with normal cell division, or cause mutations. 
These injuries to the genetic material are of a kind that may lead to disease in the individual 
exposed or they may make their effects felt in future generations. Only a few decades ago, no 
one knew these effects of either radiation or chemicals. In those days the atom had not been 
split and few of the chemicals that were to duplicate radiation had as yet been conceived in the 
test tubes of chemists. Then in 1927, a professor of zoology in a Texas university, Dr. H. J. 
Muller, found that by exposing an organism to X-radiation, he could produce mutations in 
succeeding generations. With Muller's discovery a vast new field of scientific and medical 
knowledge was opened up. Muller later received the Nobel Prize in Medicine for his 
achievement, and in a world that soon gained unhappy familiarity with the gray rains of fallout, 
even the nonscientist now knows the potential results of radiation. 

Although far less noticed, a companion discovery was made by Charlotte Auerbach and William 
Robson at the University of Edinburgh in the early 1940s. Working with mustard gas, they found 
that this chemical produces permanent chromosome abnormalities that cannot be 
distinguished from those induced by radiation. Tested on the fruit fly, the same organism 
Muller had used in his original work with X-rays, mustard gas also produced mutations. Thus 
the first chemical mutagen was discovered. Mustard gas as a mutagen has now been joined by 
a long list of other chemicals known to alter genetic material in plants and animals. To 
understand how chemicals can alter the course of heredity, we must first watch the basic 
drama of life as it is played on the stage of the living cell. The cells composing the tissues and 
organs of the body must have the power to increase in number if the body is to grow and if the 
stream of life is to be kept flowing from generation to generation. This is accomplished by the 
process of mitosis, or nuclear division. In a cell that is about to divide, changes of the utmost 
importance occur, first within the nucleus, but eventually involving the entire cell. Within the 
nucleus, the chromosomes mysteriously move and divide, ranging themselves in age-old 
patterns that will serve to distribute the determiners of heredity, the genes, to the daughter 
cells. First they assume the form of elongated threads, on which the genes are aligned, like 
beads on a string. Then each chromosome divides lengthwise (the genes dividing also). When 
the cell divides into two, half of each goes to each of the daughter cells. In this way each new 
cell will contain a complete set of chromosomes, and all the genetic information encoded 
within them. In this way the integrity of the race and of the species is preserved; in this way like 
begets like. 

A special kind of cell division occurs in the formation of the germ cells. Because the 
chromosome number for a given species is constant, the egg and the sperm, which are to unite 
to form a new individual, must carry to their union only half the species number. This is 
accomplished with extraordinary precision by a change in the behavior of the chromosomes 
that occurs at one of the divisions producing those cells. At this time the chromosomes do not 
split, but one whole chromosome of each pair goes into each daughter cell. 
In this elemental drama all life is revealed as one. The events of the process of cell division are 
common to all earthly life; neither man nor amoeba, the giant sequoia nor the simple yeast cell 
can long exist without carrying on this process of cell division. Anything that disturbs mitosis is 
therefore a grave threat to the welfare of the organism affected and to its descendants. 
'The major features of cellular organization, including, for instance, mitosis, must be much older 
than 500 million years— more nearly 1000 million,' wrote George Gaylord Simpson and his 
colleagues Pittendrigh and Tiffany in their broadly encompassing book entitled Life. 'In this 
sense the world of life, while surely fragile and complex, is incredibly durable through time- 
more durable than mountains. This durability is wholly dependent on the almost incredible 
accuracy with which the inherited information is copied from generation to generation.' 
But in all the thousand million years envisioned by these authors no threat has struck so 
directly and so forcefully at that 'incredible accuracy' as the mid-20th century threat of man- 
made radiation and man-made and man-disseminated chemicals. Sir Macfarlane Burnet, a 
distinguished Australian physician and a Nobel Prize winner, considers it 'one of the most 
significant medical features' of our time that, 'as a by-product of more and more powerful 
therapeutic procedures and the production of chemical substances outside of biological 

experiences, the normal protective barriers that kept mutagenic agents from the internal 
organs have been more and more frequently penetrated.' 

The study of human chromosomes is in its infancy, and so it has only recently become possible 
to study the effect of environmental factors upon them. It was not until 1956 that new 
techniques made it possible to determine accurately the number of chromosomes in the 
human cell— 46— and to observe them in such detail that the presence or absence of whole 
chromosomes or even parts of chromosomes could be detected. The whole concept of genetic 
damage by something in the environment is also relatively new, and is little understood except 
by the geneticists, whose advice is too seldom sought. The hazard from radiation in its various 
forms is now reasonably well understood— although still denied in surprising places. Dr. Muller 
has frequently had occasion to deplore the 'resistance to the acceptance of genetic principles 
on the part of so many, not only of governmental appointees in the policy-making positions, 
but also of so many of the medical profession.' The fact that chemicals may play a role similar 
to radiation has scarcely dawned on the public mind, nor on the minds of most medical or 
scientific workers. For this reason the role of chemicals in general use (rather than in laboratory 
experiments) has not yet been assessed. It is extremely important that this be done. 
Sir Macfarlane is not alone in his estimate of the potential danger. Dr. Peter Alexander, an 
outstanding British authority, has said that the radiomimetic chemicals 'may well represent a 
greater danger" than radiation. Dr. Muller, with the perspective gained by decades of 
distinguished work in genetics, warns that various chemicals (including groups represented by 
pesticides) 'can raise the mutation frequency as much as radiation. ..As yet far too little is 
known of the extent to which our genes, under modern conditions of exposure to unusual 
chemicals, are being subjected to such mutagenic influences.' 

The widespread neglect of the problem of chemical mutagens is perhaps due to the fact that 
those first discovered were of scientific interest only. Nitrogen mustard, after all, is not sprayed 
upon whole populations from the air; its use is in the hands of experimental biologists or of 
physicians who use it in cancer therapy. (A case of chromosome damage in a patient receiving 
such therapy has recently been reported.) But insecticides and weed killers are brought into 
intimate contact with large numbers of people. Despite the scant attention that has been given 
to the matter, it is possible to assemble specific information on a number of these pesticides, 
showing that they disturb the cell's vital processes in ways ranging from slight chromosome 
damage to gene mutation, and with consequences extending to the ultimate disaster of 
malignancy. Mosquitoes exposed to DDT for several generations turned into strange creatures 
called gynandromorphs— part male and part female. 

Plants treated with various phenols suffered profound destruction of chromosomes, changes in 
genes, a striking number of mutations, 'irreversible hereditary changes'. Mutations also 
occurred in fruit flies, the classic subject of genetics experiments, when subjected to phenol; 
these flies developed mutations so damaging as to be fatal on exposure to one of the common 
herbicides or to urethane. Urethane belongs to the group of chemicals called carbamates, from 
which an increasing number of insecticides and other agricultural chemicals are drawn. Two of 
the carbamates are actually used to prevent sprouting of potatoes in storage— precisely 
because of their proven effect in stopping cell division. Another antisprouting agent, maleic 
hydrazide, is rated a powerful mutagen. Plants treated with benzene hexachloride (BHC) or 

lindane became monstrously deformed with tumorlike swellings on their roots. Their cells grew 
in size, beingswollen with chromosomes which doubled in number. The doubling continued 
in future divisions until further cell division became mechanically impossible. The herbicide 2,4- 
D has also produced tumorlike swellings in treated plants. Chromosomes become short, thick, 
clumped together. Cell division is seriously retarded. The general effect is said to parallel closely 
that produced by Xrays. 

These are but a few illustrations; many more could be cited. As yet there has been no 
comprehensive study aimed at testing the mutagenic effects of pesticides as such. The facts 
cited above are by-products of research in cell physiology or genetics. What is urgently needed 
is a direct attack on the problem. Some scientists who are willing to concede the potent effect 
of environmental radiation on man nevertheless question whether mutagenic chemicals can, as 
a practical proposition, have the same effect. They cite the great penetrating power of 
radiation, but doubt that chemicals could reach the germ cells. Once again we are hampered by 
the fact that there has been little direct investigation of the problem in man. However, the 
finding of large residues of DDT in the gonads and germ cells of birds and mammals is strong 
evidence that the chlorinated hydrocarbons, at least, not only become widely distributed 
throughout the body but come into contact with genetic materials. Professor David E. Davis at 
Pennsylvania State University has recently discovered that a potent chemical which prevents 
cells from dividing and has had limited use in cancer therapy can also be used to cause sterility 
in birds. Sublethal levels of the chemical halt cell division in the gonads. Professor Davis has had 
some success in field trials. Obviously, then, there is little basis for the hope or belief that the 
gonads of any organism are shielded from chemicals in the environment. 
Recent medical findings in the field of chromosome abnormalities are of extreme interest and 
significance. In 1959 several British and French research teams found their independent studies 
pointing to a common conclusion— that some of humanity's ills are caused by a disturbance of 
the normal chromosome number. In certain diseases and abnormalities studied by these 
investigators the number differed from the normal. To illustrate: it is now known that all typical 
mongoloids have one extra chromosome. Occasionally this is attached to another so that the 
chromosome number remains the normal 46. As a rule, however, the extra is a separate 
chromosome, making the number 47. In such individuals, the original cause of the defect must 
have occurred in the generation preceding its appearance. A different mechanism seems to 
operate in a number of patients, both in America and Great Britain, who are suffering from a 
chronic form of leukemia. These have been found to have a consistent chromosome 
abnormality in some of the blood cells. The abnormality consists of the loss of part of a 
chromosome. In these patients the skin cells have a normal complement of chromosomes. This 
indicates that the chromosome defect did not occur in the germ cells that gave rise to these 
individuals, but represents damage to particular cells (in this case, the precursors of blood cells) 
that occurred during the life of the individual. The loss of part of a chromosome has perhaps 
deprived these cells of their 'instructions' for normal behavior. 

The list of defects linked to chromosome disturbances has grown with surprising speed since 
the opening of this territory, hitherto beyond the boundaries of medical research. One, known 
only as Klinefelter^ syndrome, involves a duplication of one of the sex chromosomes. The 
resulting individual is a male, but because he carries two of the X chromosomes (becoming XXY 
instead of XY, the normal male complement) he is somewhat abnormal. Excessive height and 

mental defects often accompany the sterility caused by this condition. In contrast, an individual 
who receives only one sex chromosome (becoming XO instead of either XX or XY) is actually 
female but lacks many of the secondary sexual characteristics. The condition is accompanied by 
various physical (and sometimes mental) defects, for of course the X chromosome carries genes 
for a variety of characteristics. This is known as Turner's syndrome. Both conditions had been 
described in medical literature long before the cause was known. 

An immense amount of work on the subject of chromosome abnormalities is being done by 
workers in many countries. A group at the University of Wisconsin, headed by Dr. Klaus Patau, 
has been concentrating on a variety of congenital abnormalities, usually including mental 
retardation, that seem to result from the duplication of only part of a chromosome, as if 
somewhere in the formation of one of the germ cells a chromosome had broken and the pieces 
had not been properly redistributed. Such a mishap is likely to interfere with the normal 
development of the embryo. According to present knowledge, the occurrence of an entire extra 
body chromosome is usually lethal, preventing survival of the embryo. Only three such 
conditions are known to be viable; one of them, of course, is mongolism. The presence of an 
extra attached fragment, on the other hand, although seriously damaging is not necessarily 
fatal, and according to the Wisconsin investigators this situation may well account for a 
substantial part of the so far unexplained cases in which a child is born with multiple defects, 
usually including mental retardation. This is so new a field of study that as yet scientists have 
been more concerned with identifying the chromosome abnormalities associated with disease 
and defective development than with speculating about the causes. It would be foolish to 
assume that any single agent is responsible for damaging the chromosomes or causing their 
erratic behavior during cell division. But can we afford to ignore the fact that we are now filling 
the environment with chemicals that have the power to strike directly at the chromosomes, 
affecting them in the precise ways that could cause such conditions? Is this not too high a price 
to pay for a sproutless potato or a mosquitoless patio? We can, if we wish, reduce this threat to 
our genetic heritage, a possession that has come down to us through some two billion years of 
evolution and selection of living protoplasm, a possession that is ours for the moment only, 
until we must pass it on to generations to come. We are doing little now to preserve its 
integrity. Although chemical manufacturers are required by law to test their materials for 
toxicity, they are not required to make the tests that would reliably demonstrate genetic effect, 
and they do not do so. 

14. One in Every Four 

THE BATTLE of living things against cancer began so long ago that its origin is lost in 
time. But it must have begun in a natural environment, in which whatever life inhabited the 
earth was subjected, for good or ill, to influences that had their origin in sun and storm and the 
ancient nature of the earth. Some of the elements of this environment created hazards to 
which life had to adjust or perish. The ultraviolet radiation in sunlight could cause malignancy. 
So could radiations from certain rocks, or arsenic washed out of soil or rocks to contaminate 
food or water supplies. The environment contained these hostile elements even before there 
was life; yet life arose, and over the millions of years it came to exist in infinite numbers and 
endless variety. Over the eons of unhurried time that is nature's, life reached an adjustment 
with destructive forces as selection weeded out the less adaptable and only the most resistant 
survived. These natural cancer-causing agents are still a factor in producing malignancy; 
however, they are few in number and they belong to that ancient array of forces to which life 
has been accustomed from the beginning. 

With the advent of man the situation began to change, for man, alone of all forms of life, can 
create cancer-producing substances, which in medical terminology are called carcinogens. A 
few man-made carcinogens have been part of the environment for centuries. An example is 
soot, containing aromatic hydrocarbons. With the dawn of the industrial era the world became 
a place of continuous, ever-accelerating change. Instead of the natural environment there was 
rapidly substituted an artificial one composed of new chemical and physical agents, many of 
them possessing powerful capacities for inducing biologic change. Against these carcinogens 
which his own activities had created man had no protection, for even as his biological heritage 
has evolved slowly, so it adapts slowly to new conditions. As a result these powerful substances 
could easily penetrate the inadequate defenses of the body. 

The history of cancer is long, but our recognition of the agents that produce it has been slow to 
mature. The first awareness that external or environmental agents could produce malignant 
change dawned in the mind of a London physician nearly two centuries ago. In 1775 Sir 
Percivall Pott declared that the scrotal cancer so common among chimney sweeps must be 
caused by the soot that accumulated on their bodies. He could not furnish the 'proof we would 
demand today, but modern research methods have now isolated the deadly chemical in soot 
and proved the correctness of his perception. For a century or more after Pott's discovery there 
seems to have been little further realization that certain of the chemicals in the human 
environment could cause cancer by repeated skin contact, inhalation, or swallowing. True, it 
had been noticed that skin cancer was prevalent among workers exposed to arsenic fumes in 
copper smelters and tin foundries in Cornwall and Wales. And it was realized that workers in 
the cobalt mines in Saxony and in the uranium mines at Joachimsthal in Bohemia were subject 
to a disease of the lungs, later identified as cancer. But these were phenomena of the pre- 
industrial era, before the flowering of the industries whose products were to pervade the 
environment of almost every living thing. 

The first recognition of malignancies traceable to the age of industry came during the last 
quarter of the 19th century. About the time that Pasteur was demonstrating the microbial 
origin of many infectious diseases, others were discovering the chemical origin of cancer skin 

cancers among workers in the new lignite industry in Saxony and in the Scottish shale industry, 
along with other cancers caused by occupational exposure to tar and pitch. By the end of the 
19th century a half-dozen sources of industrial carcinogens were known; the 20th century was 
to create countless new cancer-causing chemicals and to bring the general population into 
intimate contact with them. In the less than two centuries intervening since the work of Pott, 
the environmental situation has been vastly changed. No longer are exposures to dangerous 
chemicals occupational alone; they have entered the environment of everyone— even of 
children as yet unborn. It is hardly surprising, therefore, that we are now aware of an alarming 
increase in malignant disease. 

The increase itself is no mere matter of subjective impressions. The monthly report of the 
Office of Vital Statistics for July 1959 states that malignant growths, including those of the 
lymphatic and blood-forming tissues, accounted for 15 per cent of the deaths in 1958 
compared with only 4 per cent in 1900. Judging by the present incidence of the disease, the 
American Cancer Society estimates that 45,000,000 Americans now living will eventually 
develop cancer. This means that malignant disease will strike two out of three families. The 
situation with respect to children is even more deeply disturbing. A quarter century ago, cancer 
in children was considered a medical rarity. Today, more American school children die of cancer 
than from any other disease. So serious has this situation become that Boston has established 
the first hospital in the United States devoted exclusively to the treatment of children with 
cancer. Twelve per cent of all deaths in children between the ages of one and fourteen are 
caused by cancer. Large numbers of malignant tumors are discovered clinically in children 
under the age of five, but it is an even grimmer fact that significant numbers of such growths 
are present at or before birth. Dr. W. C. Hueper of the National Cancer Institute, a foremost 
authority on environmental cancer, has suggested that congenital cancers and cancers in 
infants may be related to the action of cancer-producing agents to which the mother has been 
exposed during pregnancy and which penetrate the placenta to act on the rapidly developing 
fetal tissues. Experiments show that the younger the animal is when it is subjected to a cancer- 
producing agent the more certain is the production of cancer. Dr. Francis Ray of the University 
of Florida has warned that 'we may be initiating cancer in the children of today by the addition 
of chemicals [to food]. ..We will not know, perhaps for a generation or two, what the effects will 
be.' . . . 

The problem that concerns us here is whether any of the chemicals we are using in our 
attempts to control nature play a direct or indirect role as causes of cancer. In terms of 
evidence gained from animal experiments we shall see that five or possibly six of the pesticides 
must definitely be rated as carcinogens. The list is greatly lengthened if we add those 
considered by some physicians to cause leukemia in human patients. Here the evidence is 
circumstantial, as it must be since we do not experiment on human beings, but it is nonetheless 
impressive. Still other pesticides will be added as we include those whose action on living 
tissues or cells may be considered an indirect cause of malignancy. One of the earliest 
pesticides associated with cancer is arsenic, occurring in sodium arsenite as a weed killer, and in 
calcium arsenate and various other compounds as insecticides. The association between arsenic 
and cancer in man and animals is historic. A fascinating example of the consequences of 
exposure to arsenic is related by Dr. Hueper in his Occupational Tumors, a classic monograph 
on the subject. The city of Reichenstein in Silesia had been for almost a thousand years the site 

of mining for gold and silver ores, and for several hundred years for arsenic ores. Over the 
centuries arsenic wastes accumulated in the vicinity of the mine shafts and were picked up by 
streams coming down from the mountains. The underground water also became contaminated, 
and arsenic entered the drinking water. For centuries many of the inhabitants of this region 
suffered from what came to be known as 'the Reichenstein disease'— chronic arsenicism with 
accompanying disorders of the liver, skin, and gastrointestinal and nervous systems. Malignant 
tumors were a common accompaniment of the disease. Reichenstein's disease is now chiefly of 
historic interest, for new water supplies were provided a quarter of a century ago, from which 
arsenic was largely eliminated. In Cordoba Province in Argentina, however, chronic arsenic 
poisoning, accompanied by arsenical skin cancers, is endemic because of the contamination of 
drinking water derived from rock formations containing arsenic. 

It would not be difficult to create conditions similar to those in Reichenstein and Cordoba by 
long continued use of arsenical insecticides. In the United States the arsenic-drenched soils of 
tobacco plantations, of many orchards in the Northwest, and of blueberry lands in the East may 
easily lead to pollution of water supplies. An arsenic-contaminated environment affects not 
only man but animals as well. A report of great interest came from Germany in 1936. In the 
area about Freiberg, Saxony, smelters for silver and lead poured arsenic fumes into the air, to 
drift out over the surrounding countryside and settle down upon the vegetation. According to 
Dr. Hueper, horses, cows, goats, and pigs, which of course fed on this vegetation, showed loss 
of hair and thickening of the skin. Deer inhabiting nearby forests sometimes had abnormal 
pigment spots and precancerous warts. One had a definitely cancerous lesion. Both domestic 
and wild animals were affected by 'arsenical enteritis, gastric ulcers, and cirrhosis of the liver.' 
Sheep kept near the smelters developed cancers of the nasal sinus; at their death arsenic was 
found in the brain, liver, and tumors. In the area there was also 'an extraordinary mortality 
among insects, especially bees. After rainfalls which washed the arsenical dust from the leaves 
and carried it along into the water of brooks and pools, a great many fish died.' . . . 
An example of a carcinogen belonging to the group of new, organic pesticides is a chemical 
widely used against mites and ticks. Its history provides abundant proof that, despite the 
supposed safeguards provided by legislation, the public can be exposed to a known carcinogen 
for several years before the slowly moving legal processes can bring the situation under control. 
The story is interesting from another standpoint, proving that what the public is asked to accept 
as 'safe' today may turn out tomorrow to be extremely dangerous. When this chemical was 
introduced in 1955, the manufacturer applied for a tolerance which would sanction the 
presence of small residues on any crops that might be sprayed. As required by law, he had 
tested the chemical on laboratory animals and submitted the results with his application. 
However, scientists of the Food and Drug Administration interpreted the tests as showing a 
possible cancer-producing tendency and the Commissioner accordingly recommended a 'zero 
tolerance', which is a way of saying that no residues could legally occur on food shipped across 
state lines. But the manufacturer had the legal right to appeal and the case was accordingly 
reviewed by a committee. The committee's decision was a compromise: a tolerance of 1 part 
per million was to be established and the product marketed for two years, during which time 
further laboratory tests were to determine whetherthe chemical was actuallya carcinogen. 
Although the committee did not say so, its decision meant that the public was to act as guinea 
pigs, testing the suspected carcinogen along with the laboratory dogs and rats. But laboratory 

animals give more prompt results, and after the two years it was evident that this miticide was 
indeed a carcinogen. Even at that point, in 1957, the Food and Drug Administration could not 
instantly rescind the tolerance which allowed residues of a known carcinogen to contaminate 
food consumed by the public. Another year was required for various legal procedures. Finally, 
in December 1958 the zero tolerance which the Commissioner had recommended in 1955 
became effective. These are by no means the only known carcinogens among pesticides. In 
laboratory tests on animal subjects, DDT has produced suspicious liver tumors. Scientists of the 
Food and Drug Administration who reported the discovery of these tumors were uncertain how 
to classify them, but felt there was some 'justification for considering them low grade hepatic 
cell carcinomas.' Dr. Hueper now gives DDT the definite rating of a 'chemical carcinogen'. 
Two herbicides belonging to the carbamate group, IPC and CIPC, have been found to play a role 
in producing skin tumors in mice. Some of the tumors were malignant. These chemicals seem to 
initiate the malignant change, which may then be completed by other chemicals of types 
prevalent in the environment. 

The weed-killer aminotriazole has caused thyroid cancer in test animals. This chemical was 
misused by a number of cranberry growers in 1959, producing residues on some of the 
marketed berries. In the controversy that followed seizure of contaminated cranberries by the 
Food and Drug Administration, the fact that the chemical actually is cancer producing was 
widely challenged, even by many medical men. The scientific facts released by the Food and 
Drug Administration clearly indicate the carcinogenic nature of aminotriazole in laboratory rats. 
When these animals were fed this chemical at the rate of 100 parts per million in the drinking 
water (or one teaspoonful of chemical in ten thousand teaspoonfuls of water) they began to 
develop thyroid tumors at the 68th week. After two years, such tumors were present in more 
than half the rats examined. They were diagnosed as various types of benign and malignant 
growths. The tumors also appeared at lower levels of feeding— in fact, a level that produced no 
effect was not found. No one knows, of course, the level at which aminotriazole may be 
carcinogenic for man, but as a professor of medicine at Harvard University, Dr. David Rutstein, 
has pointed out, the level is just as likely to be to man's disfavor as to his advantage. 
As yet insufficient time has elapsed to reveal the full effect of the new chlorinated hydrocarbon 
insecticides and of the modern herbicides. Most malignancies develop so slowly that they may 
require a considerable segment of the victim's life to reach the stage of showing clinical 
symptoms. In the early 1920s women who painted luminous figures on watch dials swallowed 
minute amounts of radium by touching the brushes to their lips; in some of these women bone 
cancers developed after a lapse of 15 or more years. A period of 15 to 30 years or even more 
has been demonstrated for some cancers caused by occupational exposures to chemical 

In contrast to these industrial exposures to various carcinogens the first exposures to DDT date 
from about 1942 for military personnel and from about 1945 for civilians, and it was not until 
the early fifties that a wide variety of pesticidal chemicals came into use. The full maturing of 
whatever seeds of malignancy have been sown by these chemicals is yet to come. 
There is, however, one presently known exception to the fact that a long period of latency is 
common to most malignancies. This exception is leukemia. Survivors of Hiroshima began to 
develop leukemia only three years after the atomic bombing, and there is now reason to 
believe the latent period may be considerably shorter. Other types of cancer may in time be 

found to have a relatively short latent period, also, but at present leukemia seems to be the 
exception to the general rule of extremely slow development. Within the period covered by the 
rise of modern pesticides, the incidence of leukemia has been steadily rising. Figures available 
from the National Office of Vital Statistics clearly establish a disturbing rise in malignant 
diseases of the bloodforming tissues. In the year 1960, leukemia alone claimed 12,290 victims. 
Deaths from all types of malignancies of blood and lymph totaled 25,400, increasing sharply 
from the 16,690 figure of 1950. In terms of deaths per 100,000 of population, the increase is 
from 11.1 in 1950 to 14. 1 in 1960 The increase is by no means confined to the United States; in 
all countries the recorded deaths from leukemia at all ages are rising at a rate of 4 to 5 percent 
a year. What does it mean? To what lethal agent or agents, new to our environment, are people 
now exposed with increasing frequency? 

Such world-famous institutions as the Mayo Clinic admit hundreds of victims of these diseases 
of the blood-forming organs. Dr. Malcolm Hargraves and his associates in the Hematology 
Department at the Mayo Clinic report that almost without exception these patients have had a 
history of exposure to various toxic chemicals, including sprays which contain DDT, chlordane, 
benzene, lindane, and petroleum distillates. 

Environmental diseases related to the use of various toxic substances have been increasing, 
'particularly during the past ten years', Dr. Hargraves believes. From extensive clinical 
experience he believes that 'the vast majority of patients suffering from the blood dyscrasias 
and lymphoid diseases have a significant history of exposure to the various hydrocarbons which 
in turn includes most of the pesticides of today. A careful medical history will almost invariably 
establish such a relationship.' This specialist now has a large number of detailed case histories 
based on every patient he has seen with leukemias, aplastic anemias, Hodgkin's disease, and 
other disorders of the blood and blood-forming tissues. 'They had all been exposed to these 
environmental agents, with a fair amount of exposure,' he reports. What do these case 
histories show? One concerned a housewife who abhorred spiders. In mid-August she had gone 
into her basement with an aerosol spray containing DDT and petroleum distillate. She sprayed 
the entire basement thoroughly, under the stairs, in the fruit cupboards and in all the protected 
areas around ceiling and rafters. As she finished the spraying she began to feel quite ill, with 
nausea and extreme anxiety and nervousness. Within the next few days she felt better, 
however, and apparently not suspecting the cause of her difficulty, she repeated the entire 
procedure in September, running through two more cycles of spraying, falling ill, recovering 
temporarily, spraying again. After the third use of the aerosol new symptoms developed: fever, 
pains in the joints and general malaise, acute phlebitis in one leg. When examined by Dr. 
Hargraves she was found to be suffering from acute leukemia. She died within the following 

Another of Dr. Hargraves' patients was a professional man who had his office in an old building 
infested by roaches. Becoming embarrassed by the presence of these insects, he took control 
measures in his own hands. He spent most of one Sunday spraying the basement and all 
secluded areas. The spray was a 25 per cent DDT concentrate suspended in a solvent containing 
methylated naphthalenes. Within a short time he began to bruise and bleed. He entered the 
clinic bleeding from a number of hemorrhages. Studies of his blood revealed a severe 
depression of the bone marrow called aplastic anemia. During the next five and one half 
months he received 59 transfusions in addition to other therapy. There was partial recovery but 

about nine years later a fatal leukemia developed. Where pesticides are involved, the chemicals 
that figure most prominently in the case histories are DDT, lindane, benzene hexachloride, the 
nitrophenols, the common moth crystal paradichlorobenzene, chlordane, and, of course, the 
solvents in which they are carried. As this physician emphasizes, pure exposure to a single 
chemical is the exception, rather than the rule. The commercial product usually contains 
combinations of several chemicals, suspended in a petroleum distillate plus some dispersing 
agent. The aromatic cyclic and unsaturated hydrocarbons of the vehicle may themselves be a 
major factor in the damage done the blood-forming organs. From the practical rather than the 
medical standpoint this distinction is of little importance, however, because these petroleum 
solvents are an inseparable part of most common spraying practices. 

The medical literature of this and other countries contains many significant cases that support 
Dr. Hargraves' belief in a cause-and-effect relation between these chemicals and leukemia and 
other blood disorders. They concern such everyday people as farmers caught in the 'fallout' of 
their own spray rigs or of planes, a college student who sprayed his study for ants and remained 
in the room to study, a woman who had installed a portable lindane vaporizer in her home, a 
worker in a cotton field that had been sprayed with chlordane and toxaphene. They carry, half 
concealed within their medical terminology, stories of such human tragedies as that of two 
young cousins in Czechoslovakia, boys who lived in the same town and had always worked and 
played together. Their last and most fateful employment was at a farm cooperative where it 
was their job to unload sacks of an insecticide (benzene hexachloride). Eight months later one 
of the boys was stricken with acute leukemia. In nine days he was dead. At about this time his 
cousin began to tire easily and to run a temperature. Within about three months his symptoms 
became more severe and he, too, was hospitalized. Again the diagnosis was acute leukemia, 
and again the disease ran its inevitably fatal course. 

And then there is the case of a Swedish farmer, strangely reminiscent of that of the Japanese 
fisherman Kuboyama of the tuna vessel the Lucky Dragon. Like Kuboyama, the farmer had been 
a healthy man, gleaning his living from the land as Kuboyama had taken his from the sea. For 
each man a poison drifting out of the sky carried a death sentence. For one, it was radiation- 
poisoned ash; for the other, chemical dust. The farmer had treated about 60 acres of land with 
a dust containing DDT and benzene hexachloride. As he worked puffs of wind brought little 
clouds of dust swirling about him. 'In the evening he felt unusually tired, and during the 
subsequent days he had a general feeling of weakness, with backache and aching legs as well as 
chills, and was obliged to take to his bed,' says a report from the Medical Clinic at Lund. 'His 
condition became worse, however, and on May 19 [a week after the spraying] he applied for 
admission to the local hospital.' He had a high fever and his blood count was abnormal. He was 
transferred to the Medical Clinic, where, after an illness of two and one half months, he died. A 
post-mortem examination revealed a complete wasting away of the bone marrow. . . . 
How a normal and necessary process such as cell division can become altered so that it is alien 
and destructive is a problem that has engaged the attention of countless scientists and untold 
sums of money. What happens in a cell to change its orderly multiplication into the wild and 
uncontrolled proliferation of cancer? When answers are found they will almost certainly be 
multiple. Just as cancer itself is a disease that wears many guises, appearing in various forms 
that differ in their origin, in the course of their development, and in the factors that influence 
their growth or regression, so there must be a corresponding variety of causes. Yet underlying 

them all, perhaps, only a few basic kinds of injuries to the cell are responsible. Here and there, 
in research widely scattered and sometimes not undertaken as a cancer study at all, we see 
glimmerings of the first light that may one day illuminate this problem. 

Again we find that only by looking at some of the smallest units of life, the cell and its 
chromosomes, can we find that wider vision needed to penetrate such mysteries. Here, in this 
microcosm, we must look for those factors that somehow shift the marvelously functioning 
mechanisms of the cell out of their normal patterns. One of the most impressive theories of the 
origin of cancer cells was developed by a German biochemist, Professor Otto Warburg of the 
Max Planck Institute of Cell Physiology. Warburg has devoted a lifetime of study to the complex 
processes of oxidation within the cell. Out of this broad background of understanding came a 
fascinating and lucid explanation of the way a normal cell can become malignant. Warburg 
believes that either radiation or a chemical carcinogen acts by destroying the respiration of 
normal cells, thus depriving them of energy. This action may result from minute doses often 
repeated. The effect, once achieved, is irreversible. The cells not killed outright by the impact of 
such a respiratory poison struggle to compensate for the loss of energy. They can no longer 
carry on that extraordinary and efficient cycle by which vast amounts of ATP are produced, but 
are thrown back on a primitive and far less efficient method, that of fermentation. The struggle 
to survive by fermentation continues for a long period of time. It continues through ensuing cell 
divisions, so that all the descendant cells have this abnormal method of respiration. Once a cell 
has lost its normal respiration it cannot regain it— not in a year, not in a decade or in many 
decades. But little by little, in this grueling struggle to restore lost energy, those cells that 
survive begin to compensate by increased fermentation. It is a Darwinian struggle, in which only 
the most fit or adaptable survive. At last they reach the point where fermentation is able to 
produce as much energy as respiration. At this point, cancer cells may be said to have been 
created from normal body cells. 

Warburg's theory explains many otherwise puzzling things. The long latent period of most 
cancers is the time required for the infinite number of cell divisions during which fermentation 
is gradually increasing after the initial damage to respiration. The time required for 
fermentation to become dominant varies in different species because of different fermentation 
rates: a short time in the rat, in which cancers appear quickly, a long time (decades even) in 
man, in whom the development of malignancy is a deliberate process. 

The Warburg theory also explains why repeated small doses of a carcinogen are more 
dangerous under some circumstances than a single large dose. The latter may kill the cells 
outright, whereas the small doses allow some to survive, though in a damaged condition. These 
survivors may then develop into cancer cells. This is why there is no 'safe' dose of a carcinogen. 
In Warburg's theory we also find explanation of an otherwise incomprehensible fact— that one 
and the same agent can be useful in treating cancer and can also cause it. This, as everyone 
knows, is true of radiation, which kills cancer cells but may also cause cancer. It is also true of 
many of the chemicals now used against cancer. Why? Both types of agents damage 
respiration. Cancer cells already have a defective respiration, so with additional damage they 
die. The normal cells, suffering respiratory damage for the first time, are not killed but are set 
on the path that may eventually lead to malignancy. 

Warburg's ideas received confirmation in 1953 when other workers were able to turn normal 
cells into cancer cells merely by depriving them of oxygen intermittently over long periods. 

Then in 1961 other confirmation came, this time from living animals rather than tissue cultures. 
Radioactive tracer substances were injected into cancerous mice. Then by careful 
measurements of their respiration, it was found that the fermentation rate was markedly above 
normal, just as Warburg had foreseen. Measured by the standards established by Warburg, 
most pesticides meet the criterion of the perfect carcinogen too well for comfort. As we have 
seen in the preceding chapter, many of the chlorinated hydrocarbons, the phenols, and some 
herbicides interfere with oxidation and energy production within the cell. By these means they 
may be creating sleeping cancer cells, in which an irreversible malignancy will slumber long and 
undetected until finally— its cause long forgotten and even unsuspected— it flares into the open 
as recognizable cancer. 

Another path to cancer may be by way of the chromosomes. Many of the most distinguished 
research men in this field look with suspicion on any agent that damages the chromosomes, 
interferes with cell division, or causes mutations. In the view of these men any mutation is a 
potential cause of cancer. Although discussions of mutations usually refer to those in the germ 
cells, which may then make their effect felt in future generations, there may also be mutations 
in the body cells. According to the mutation theory of the origin of cancer, a cell, perhaps under 
the influence of radiation or of a chemical, develops a mutation that allows it to escape the 
controls the body normally asserts over cell division. It is therefore able to multiply in a wild 
and unregulated manner. The new cells resulting from these divisions have the same ability to 
escape control, and in time enough such cells have accumulated to constitute a cancer. Other 
investigators point to the fact that the chromosomes in cancer tissue are unstable; they tend to 
be broken or damaged, the number may be erratic, there may even be double sets. 
The first investigators to trace chromosome abnormalities all the way to actual malignancy 
were Albert Levan and John J. Biesele, working at the Sloan- Kettering Institute in New York. As 
to which came first, the malignancy or the disturbance of the chromosomes, these workers say 
without hesitation that 'the chromosomal irregularities precede the malignancy.' Perhaps, they 
speculate, after the initial chromosome damage and the resulting instability there is a long 
period of trial and error through many cell generations (the long latent period of malignancy) 
during which a collection of mutations is finally accumulated which allow the cells to escape 
from control and embark on the unregulated multiplication that is cancer. 
Ojvind Winge, one of the early proponents of the theory of chromosome instability, felt that 
chromosome doublings were especially significant. Is it coincidence, then, that benzene 
hexachloride and its relative, lindane, are known through repeated observations to double the 
chromosomes in experimental plants —and that these same chemicals have been implicated in 
many well-documented cases of fatal anemias? And what of the many other pesticides that 
interfere with cell division, break chromosomes, cause mutations? It is easy to see why 
leukemia should be one of the most common diseases to result from exposure to radiation or 
to chemicals that imitate radiation. The principal targets of physical or chemical mutagenic 
agents are cells that are undergoing especially active division. This includes various tissues but 
most importantly those engaged in the production of blood. The bone marrow is the chief 
producer of red blood cells throughout life, sending some 10 million new cells per second into 
the bloodstream of man. White corpuscles are formed in the lymph glands and in some of the 
marrow cells at a variable, but still prodigious, rate. 

Certain chemicals, again reminding us of radiation products like Strontium 90, have a peculiar 
affinity for the bone marrow. Benzene, a frequent constituent of insecticida I solvents, lodges in 
the marrow and remains deposited there for periods known to be as long as 20 months. 
Benzene itself has been recognized in medical literature for many years as a cause of leukemia. 
The rapidly growing tissues of a child would also afford conditions most suitable for the 
development of malignant cells. Sir Macfarlane Burnet has pointed out that not only is 
leukemia increasing throughout the world but it has become most common in the three- to 
four-yea rage bracket, an age incidence shown by no other disease. According to this authority, 
'The peak between three and four years of age can hardly have any other interpretation than 
exposure of the young organism to a mutagenic stimulus around the time of birth.' 
Another mutagen known to produce cancer is urethane. When pregnant mice are treated with 
this chemical not only do they develop cancer of the lung but their young do, also. The only 
exposure of the infant mice to urethane was prenatal in these experiments, proving that the 
chemical must have passed through the placenta. In human populations exposed to urethane 
or related chemicals there is a possibility that tumors will develop in infants through prenatal 
exposure, as Dr. Hueper has warned. Urethane as a carbamate is chemically related to the 
herbicides IPC and CIPC. Despite the warnings of cancer experts, carbamates are now widely 
used, not only as insecticides, weed killers, and fungicides, but also in a variety of products 
including plasticizers, medicines, clothing, and insulating materials. . . . 

The road to cancer may also be an indirect one. A substance that is not a carcinogen in the 
ordinary sense may disturb the normal functioning of some part of the body in such a way that 
malignancy results. Important examples are the cancers, especially of the reproductive system, 
that appea r to be linked with disturbances of the balance of sex hormones; these disturbances, 
in turn, may in some cases be the result of something that affects the ability of the liver to 
preserve a proper level of these hormones. The chlorinated hydrocarbons are precisely the kind 
of agent that can bring about this kind of indirect carcinogenesis, because all of them are toxic 
in some degree to the liver. The sex hormones are, of course, normally present in the body and 
perform a necessary growth-stimulating function in relation to the various organs of 
reproduction. But the body has a built-in protection against excessive accumulations, for the 
liver acts to keep a proper balance between male and female hormones (both are produced in 
the bodies of both sexes, although in different amounts) and to prevent an excess accumulation 
of either. It cannot do so, however, if it has been damaged by disease or chemicals, or if the 
supply of the B-complex vitamins has been reduced. Under these conditions the estrogens build 
up to abnormally high levels. 

What are the effects? In animals, at least, there is abundant evidence from experiments. In one 
such, an investigator at the Rockefeller Institute for Medical Research found that rabbits with 
livers damaged by disease show a very high incidence of uterine tumors, thought to have 
developed because the liver was no longer able to inactivate the estrogens in the blood, so that 
they 'subsequently rose to a carcinogenic level.' Extensive experiments on mice, rats, guinea 
pigs, and monkeys show that prolonged administration of estrogens (not necessarily at high 
levels) has caused changes in the tissues of the reproductive organs, 'varying from benign 
overgrowth to definite malignancy'. Tumors of the kidneys have been induced in hamsters by 
administering estrogens. Although medical opinion is divided on the question, much evidence 
exists to support the view that similar effects may occur in human tissues. Investigators at the 

Royal Victoria Hospital at McGill University found two thirds of 150 cases of uterine cancer 
studied by them gave evidence of abnormally high estrogen levels. In 90 per cent of a later 
series of 20 cases there was similar high estrogen activity. 

It is possible to have liver damage sufficient to interfere with estrogen elimination without 
detection of the damage by any tests now available to the medical profession. This can easily be 
caused by the chlorinated hydrocarbons, which, as we have seen, set up changes in liver cells at 
very low levels of intake. They also cause loss of the B vitamins. This, too, is extremely 
important, for other chains of evidence show the protective role of these vitamins against 
cancer. The late C. P. Rhoads, onetime director of the Sloan-Kettering Institute for Cancer 
Research, found that test animals exposed to a very potent chemical carcinogen developed no 
cancer if they had been fed yeast, a rich source of the natural B vitamins. A deficiency of these 
vitamins has been found to accompany mouth cancer and perhaps cancer of other sites in the 
digestive tract. This has been observed not only in the United States but in the far northern 
parts of Sweden and Finland, where the diet is ordinarily deficient in vitamins. Groups prone to 
primary liver cancer, as for example the Bantu tribes of Africa, are typically subject to 
malnutrition. Cancer of the male breast is also prevalent in parts of Africa, associated with liver 
disease and malnutrition. In postwar Greece enlargement of the male breast was a common 
accompaniment of periods of starvation. 

In brief, the argument for the indirect role of pesticides in cancer is based on their proven 
ability to damage the liver and to reduce the supply of B vitamins, thus leading to an increase in 
the 'endogenous' estrogens, or those produced by the body itself. Added to these are the wide 
variety of synthetic estrogens to which we are increasingly exposed— those in cosmetics, drugs, 
foods, and occupational exposures. The combined effect is a matter that warrants the most 
serious concern. . . . 

Human exposures to cancer-producing chemicals (including pesticides) are uncontrolled and 
they are multiple. An individual may have many different exposures to the same chemical. 
Arsenic is an example. It exists in the environment of every individual in many different guises: 
as an air pollutant, a contaminant of water, a pesticide residue on food, in medicines, 
cosmetics, wood preservatives, or as a coloring agent in paints and inks. It is quite possible that 
no one of these exposures alone would be sufficient to precipitate malignancy— yet any single 
supposedly 'safe dose' may be enough to tip the scales that are already loaded with other 'safe 
doses'. Or again the harm may be done by two or more different carcinogens acting together, 
so that there is a summation of their effects. The individual exposed to DDT, for example, is 
almost certain to be exposed to other liver-damaging hydrocarbons, which are so widely used 
as solvents, paint removers, degreasing agents, dry-cleaning fluids, and anesthetics. What then 
can be a 'safe dose' of DDT? The situation is made even more complicated by the fact that one 
chemical may act on another to alter its effect. Cancer may sometimes require the 
complementary action of two chemicals, one of which sensitizes the cell or tissue so that it may 
later, under the action of another or promoting agent, develop true malignancy. Thus, the 
herbicides IPC and CIPC may act as initiators in the production of skin tumors, sowing the seeds 
of malignancy that may be brought into actual being by something else— perhaps a common 

There may be interaction, too, between a physical and a chemical agent. Leukemia may occur 
as a two-step process, the malignant change being initiated by X-radiation, the promoting 

action being supplied by a chemical, as, for example, urethane. The growing exposure of the 
population to radiation from various sources, plus the many contacts with a host of chemicals 
suggest a grave new problem for the modern world. The pollution of water supplies with 
radioactive materials poses another problem. Such materials, present as contaminants in water 
that also contains chemicals, may actually change the nature of the chemicals by the impact of 
ionizing radiation, rearranging their atoms in unpredictable ways to create new chemicals. 
Water pollution experts throughout the United States are concerned by the fact that 
detergents are now a troublesome and practically universal contaminant of public water 
supplies. There is no practical way to remove them by treatment. Few detergents are known to 
be carcinogenic, but in an indirect way they may promote cancer by acting on the lining of the 
digestive tract, changing the tissues so that they more easily absorb dangerous chemicals, 
thereby aggravating their effect. But who can foresee and control this action? In the 
kaleidoscope of shifting conditions, what dose of a carcinogen can be 'safe' except a zero dose? 
We tolerate cancer-causing agents in our environment at our peril, as was clearly illustrated by 
a recent happening. In the spring of 1961 an epidemic of liver cancer appeared among rainbow 
trout in many federal, state, and private hatcheries. Trout in both eastern and western parts of 
the United States were affected; in some areas practically 100 per cent of the trout over three 
years of age developed cancer. This discovery was made because of a preexisting arrangement 
between the Environmental Cancer Section of the National Cancer Institute and the Fish and 
Wildlife Service for the reporting of all fish with tumors, so that early warning might be had of a 
cancer hazard to man from water contaminants. 

Although studies are still underway to determine the exact cause of this epidemic over so wide 
an area, the best evidence is said to point to some agent present in the prepared hatchery 
feeds. These contain an incredible variety of chemical additives and medicinal agents in 
addition to the basic foodstuffs. The story of the trout is important for many reasons, but 
chiefly as an example of what can happen when a potent carcinogen is introduced into the 
environment of any species. Dr. Hueper has described this epidemic as a serious warning that 
greatly increased attention must be given to controlling the number and variety of 
environmental carcinogens. 'If such preventive measures are not taken,' says Dr. Hueper, 'the 
stage will be set at a progressive rate for the future occurrence of a similar disaster to the 
human population.' The discovery that we are, as one investigator phrased it, living in a 'sea of 
carcinogens' is of course dismaying and may easily lead to reactions of despair and defeatism. 
'Isn't it a hopeless situation?' is the common reaction. 'Isn't it impossible even to attempt to 
eliminate these cancer-producing agents from our world? Wouldn't it be better not to waste 
time trying, but instead to put all our efforts into research to find a cure for cancer?' 
When this question is put to Dr. Hueper, whose years of distinguished work in cancer make his 
opinion one to respect, his reply is given with the thoughtfulness of one who has pondered it 
long, and has a lifetime of research and experience behind his judgment. Dr. Hueper believes 
that our situation with regard to cancer today is very similar to that which faced mankind with 
regard to infectious diseases in the closing years of the 19th century. The causative relation 
between pathogenic organisms and many diseases had been established through the brilliant 
work of Pasteur and Koch. Medical men and even the general public were becoming aware that 
the human environment was inhabited by an enormous number of microorganisms capable of 
causing disease, just as today carcinogens pervade our surroundings. Most infectious diseases 

have now been brought under a reasonable degree of control and some have been practically 
eliminated. This brilliant medical achievement came about by an attack that was twofold— that 
stressed prevention as well as cure. Despite the prominence that 'magic bullets' and 'wonder 
drugs' hold in the layman's mind, most of the really decisive battles in the war against 
infectious disease consisted of measures to eliminate disease organisms from the environment. 
An example from history concerns the great outbreak of cholera in London more than one 
hundred years ago. A London physician, John Snow, mapped the occurrence of cases and found 
they originated in one area, all of whose inhabitants drew their water from one pump located 
on Broad Street. In a swift and decisive practice of preventive medicine, Dr. Snow removed the 
handle from the pump. The epidemic was brought under control — not by a magic pill that killed 
the (then unknown) organism of cholera, but by eliminating the organism from the 
environment. Even therapeutic measures have the important result not only of curing the 
patient but of reducing the foci of infection. The present comparative rarity of tuberculosis 
results in large measure from the fact that the average person now seldom comes into contact 
with the tubercle bacillus. Today we find our world filled with cancer-producing agents. An 
attack on cancer that is concentrated wholly or even largely on therapeutic measures (even 
assuming a 'cure' could be found) in Dr. Hueper's opinion will fail because it leaves untouched 
the great reservoirs of carcinogenic agents which would continue to claim new victims faster 
than the as yet elusive 'cure' could allay the disease. 

Why have we been slow to adopt this common-sense approach to the cancer problem? 
Probably 'the goal of curing the victims of cancer is more exciting, more tangible, more 
glamorous and rewarding than prevention,' says Dr. Hueper. Yet to prevent cancer from ever 
being formed is 'definitely more humane' and can be 'much more effective than cancer cures'. 
Dr. Hueper has little patience with the wishful thinking that promises 'a magic pill that we shall 
take each morning before breakfast' as protection against cancer. Part of the public trust in 
such an eventual outcome results from the misconception that cancer is a single, though 
mysterious disease, with a single cause and, hopefully, a single cure. This of course is far from 
the known truth. Just as environmental cancers are induced by a wide variety of chemical and 
physical agents, so the malignant condition itself is manifested in many different and 
biologically distinct ways. The long promised 'breakthrough', when or if it comes, cannot be 
expected to be a panacea for all types of malignancy. Although the search must be continued 
for therapeutic measures to relieve and to cure those who have already become victims of 
cancer, it is a disservice to humanity to hold out the hope that the solution will come suddenly, 
in a single master stroke. It will come slowly, one step at a time. Meanwhile as we pour our 
millions into research and invest all our hopes in vast programs to find cures for established 
cases of cancer, we are neglecting the golden opportunity to prevent, even while we seek to 

The task is by no means a hopeless one. In one important respect the outlook is more 
encouraging than the situation regarding infectious disease at the turn of the century. The 
world was then full of disease germs, as today it is full of carcinogens. But man did not put the 
germs into the environment and his role in spreading them was involuntary. In contrast, man 
has put the vast majority of carcinogens into the environment, and he can, if he wishes, 
eliminate many of them. The chemical agents of cancer have become entrenched in our world 
in two ways: first, and ironically, through man's search for a better and easier way of life; 

second, because the manufacture and sale of such chemicals has become an accepted part of 
our economy and our way of life. It would be unrealistic to suppose that all chemical 
carcinogens can or will be eliminated from the modern world. But a very large proportion are 
by no means necessities of life. By their elimination the total load of carcinogens would be 
enormously lightened, and the threat that one in every four will develop cancer would at least 
be greatly mitigated. The most determined effort should be made to eliminate those 
carcinogens that now contaminate our food, our water supplies, and our atmosphere, because 
these provide the most dangerous type of contact— minute exposures, repeated over and over 
throughout the years. 

Among the most eminent men in cancer research are many others who share Dr. Hueper's 
belief that malignant diseases can be reduced significantly by determined efforts to identify the 
environmental causes and to eliminate them or reduce their impact. For those in whom cancer 
is already a hidden or a visible presence, efforts to find cures must of course continue. But for 
those not yet touched by the disease and certainly for the generations as yet unborn, 
prevention is the imperative need. 

15. Nature Fights Back 

TO HAVE RISKED so much in our efforts to mold nature to our satisfaction and yet to 
have failed in achieving our goal would indeed be the final irony. Yet this, it seems, is our 
situation. The truth, seldom mentioned but there for anyone to see, is that nature is not so 
easily molded and that the insects are finding ways to circumvent our chemical attacks on 

'The insect world is nature's most astonishing phenomenon,' said the Dutch biologist C. J. 
Briejer. 'Nothing is impossible to it; the most improbable things commonly occur there. One 
who penetrates deeply into its mysteries is continually breathless with wonder. He knows that 
anything can happen, and that the completely impossible often does.' The 'impossible' is now 
happening on two broad fronts. By a process of genetic selection, the insects are developing 
strains resistant to chemicals. This will be discussed in the following chapter. But the broader 
problem, which we shall look at now, is the fact that our chemical attack is weakening the 
defenses inherent in the environment itself, defenses designed to keep the various species in 
check. Each time we breach these defenses a horde of insects pours through. 
From all over the world come reports that make it clear we are in a serious predicament. At the 
end of a decade or more of intensive chemical control, entomologists were finding that 
problems they had considered solved a few years earlier had returned to plague them. And new 
problems had arisen as insects once present only in insignificant numbers had increased to the 
status of serious pests. By their very nature chemical controls are self-defeating, for they have 
been devised and applied without taking into account the complex biological systems against 
which they have been blindly hurled. The chemicals may have been pretested against a few 
individual species, but not against living communities. In some quarters nowadays it is 
fashionable to dismiss the balance of nature as a state of affairs that prevailed in an earlier, 
simpler world— a state that has now been so thoroughly upset that we might as well forget it. 
Some find this a convenient assumption, but as a chart for a course of action it is highly 
dangerous. The balance of nature is not the same today as in Pleistocene times, but it is still 
there: a complex, precise, and highly integrated system of relationships between living things 
which cannot safely be ignored any more than the law of gravity can be defied with impunity by 
a man perched on the edge of a cliff. The balance of nature is not a status quo; it is fluid, ever 
shifting, in a constant state of adjustment. Man, too, is part of this balance. Sometimes the 
balance is in his favor; sometimes— and all too often through his own activities— it is shifted to 
his disadvantage. 

Two critically important facts have been overlooked in designing the modern insect control 
programs. The first is that the really effective control of insects is that applied by nature, not by 
man. Populations are kept in check by something the ecologists call the resistance of the 
environment, and this has been so since the first life was created. The amount of food 
available, conditions of weather and climate, the presence of competing or predatory species, 
all are critically important. 'The greatest single factor in preventing insects from overwhelming 
the rest of the world is the internecine warfare which they carry out among themselves,' said 
the entomologist Robert Metcalf. Yet most of the chemicals now used kill all insects, our friends 
and enemies alike. 

The second neglected fact is the truly explosive power of a species to reproduce once the 
resistance of the environment has been weakened. The fecundity of many forms of life is 
almost beyond our power to imagine, though now and then we have suggestive glimpses. I 
remember from student days the miracle that could be wrought in a jar containing a simple 
mixture of hay and water merely by adding to it a few drops of material from a mature culture 
of protozoa. Within a few days the jar would contain a whole galaxy of whirling, darting life- 
uncountable trillions of the slipper animalcule, Paramecium, each small as a dust grain, all 
multiplying without restraint in their temporary Eden of favorable temperatures, abundant 
food, absence of enemies. Or I think of shore rocks white with barnacles as far as the eye can 
see, or of the spectacle of passing through an immense school of jellyfish, mile after mile, with 
seemingly no end to the pulsing, ghostly forms scarcely more substantial than the water itself. 
We see the miracle of nature's control at work when the cod move through winter seas to their 
spawning grounds, where each female deposits several millions of eggs. The sea does not 
become a solid mass of cod as it would surely do if all the progeny of all the cod were to 
survive. The checks that exist in nature are such that out of the millions of young produced by 
each pair only enough, on the average, survive to adulthood to replace the parent fish. 
Biologists used to entertain themselves by speculating as to what would happen if, through 
some unthinkable catastrophe, the natural restraints were thrown off and all the progeny of a 
single individual survived. Thus Thomas Huxley a century ago calculated that a single female 
aphis (which has the curious power of reproducing without mating) could produce progeny in a 
single year's time whose total weight would equal that of the inhabitants of the Chinese empire 
of his day. Fortunately for us such an extreme situation is only theoretical, but the dire results 
of upsetting nature's own arrangements are well known to students of animal populations. The 
stockman's zeal for eliminating the coyote has resulted in plagues of field mice, which the 
coyote formerly controlled. The oft repeated story of the Kaibab deer in Arizona is another case 
in point. At one time the deer population was in equilibrium with its environment. A number of 
predators— wolves, pumas, and coyotes— prevented the deer from outrunning their food 
supply. Then a campaign was begun to 'conserve' the deer by killing off their enemies. Once the 
predators were gone, the deer increased prodigiously and soon there was not enough food for 
them. The browse line on the trees went higher and higher as they sought food, and in time 
many more deer were dying of starvation than had formerly been killed by predators. The 
whole environment, moreover, was damaged by their desperate efforts to find food. 
The predatory insects of field and forests play the same role as the wolves and coyotes of the 
Kaibab. Kill them off and the population of the prey insect surges upward. No one knows how 
many species of insects inhabit the earth because so many are yet to be identified. But more 
than 700,000 have already been described. This means that in terms of the number of species, 
70 to 80 per cent of the earth's creatures are insects. The vast majority of these insects are held 
in check by natural forces, without any intervention by man. If this were not so, it is doubtful 
that any conceivable volume of chemicals —or any other methods— could possibly keep down 
their populations. The trouble is that we are seldom aware of the protection afforded by 
natural enemies until it fails. Most of us walk unseeing through the world, unaware alike of its 
beauties, its wonders, and the strange and sometimes terrible intensity of the lives that are 
being lived about us. So it is that the activities of the insect predators and parasites are known 
to few. 

Perhaps we may have noticed an oddly shaped insect of ferocious mien on a bush in the garden 
and been dimly aware that the praying mantis lives at the expense of other insects. But we see 
with understanding eye only if we have walked in the garden at night and here and there with a 
flashlight have glimpsed the mantis stealthily creeping upon her prey. Then we sense 
something of the drama of the hunter and the hunted. Then we begin to feel something of that 
relentlessly pressing force by which nature controls her own. The predators— insects that kill 
and consume other insects— are of many kinds. Some are quick and with the speed of swallows 
snatch their prey from the air. Others plod methodically along a stem, plucking off and 
devouring sedentary insects like the aphids. The yellowjackets capture soft-bodied insects and 
feed the juices to their young. Mudda u be r wasps build columned nests of mud under the caves 
of houses and stock them with insects on which their young will feed. The horseguard wasp 
hovers above herds of grazing cattle, destroying the blood-sucking flies that torment them. The 
loudly buzzing syrphid fly, often mistaken for a bee, lays its eggs on leaves of aphis-infested 
plants; the hatching larvae then consume immense numbers of aphids. Ladybugs or lady 
beetles are among the most effective destroyers of aphids, scale insects, and other plant-eating 
insects. Literally hundreds of aphids are consumed by a single ladybug to stoke the little fires of 
energy which she requires to produce even a single batch of eggs. 

Even more extraordinary in their habits are the parasitic insects. These do not kill their hosts 
outright. Instead, by a variety of adaptations they utilize their victims for the nurture of their 
own young. They may deposit their eggs within the larvae or eggs of their prey, so that their 
own developing young may find food by consuming the host. Some attach their eggs to a 
caterpillar by means of a sticky solution; on hatching, the larval parasite bores through the skin 
of the host. Others, led by an instinct that simulates foresight, merely lay their eggs on a leaf so 
that a browsing caterpillar will eat them inadvertently. 

Everywhere, in field and hedgerow and garden and forest, the insect predators and parasites 
are at work. Here, above a pond, the dragonflies dart and the sun strikes fire from their wings. 
So their ancestors sped through swamps where huge reptiles lived. Now, as in those ancient 
times, the sharp-eyed capture mosquitoes in the air, scooping them in with basket-shaped legs. 
In the waters below, their young, the dragonfly nymphs, or naiads, prey on the aquatic stages 
of mosquitoes and other insects. Or there, almost invisible against a leaf, is the lacewing, with 
green gauze wings and golden eyes, shy and secretive, descendant of an ancient race that lived 
in Permian times. The adult lacewing feeds mostly on plant nectars and the honeydew of 
aphids, and in time she lays her eggs, each on the end of a long stalk which she fastens to a leaf. 
From these emerge her children— strange, bristled larvae called aphis lions, which live by 
preying on aphids, scales, or mites, which they capture and suck dry of fluid. Each may consume 
several hundred aphids before the ceaseless turning of the cycle of its life brings the time when 
it will spin a white silken cocoon in which to pass the pupa stage. 

And there are many wasps, and flies as well, whose very existence depends on the destruction 
of the eggs or larvae of other insects through parasitism. Some of the egg parasites are 
exceedingly minute wasps, yet by their numbers and their great activity they hold down the 
abundance of many crop-destroying species. All these small creatures are working— working in 
sun and rain, during the hours of darkness, even when winter's grip has damped down the fires 
of life to mere embers. Then this vital force is merely smoldering, awaiting the time to flare 
again into activity when spring awakens the insect world. Meanwhile, under the white blanket 

of snow, below the frostha rdened soil, in crevices in the bark of trees, and in sheltered caves, 
the parasites and the predators have found ways to tide themselves over the season of cold. 
The eggs of the mantis are secure in little cases of thin parchment attached to the branch of a 
shrub by the mother who lived her life span with the summer that is gone. 
The female Polistes wasp, taking shelter in a forgotten corner of some attic, carries in her body 
the fertilized eggs, the heritage on which the whole future of her colony depends. She, the lone 
survivor, will start a small paper nest in the spring, lay a few eggs in its cells, and carefully rear a 
small force of workers. With their help she will then enlarge the nest and develop the colony. 
Then the workers, foraging ceaselessly through the hot days of summer, will destroy countless 
caterpillars. Thus, through the circumstances of their lives, and the nature of our own wants, all 
these have been our allies in keeping the balance of nature tilted in our favor. Yet we have 
turned our artillery against our friends. The terrible danger is that we have grossly 
underestimated their value in keeping at bay a dark tide of enemies that, without their help, 
can overrun us. 

The prospect of a general and permanent lowering of environmental resistance becomes grimly 
and increasingly real with each passing year as the number, variety, and destructiveness of 
insecticides grows. With the passage of time we may expect progressively more serious 
outbreaks of insects, both disease-carrying and crop-destroying species, in excess of anything 
we have ever known. 'Yes, but isn't this all theoretical?' you may ask. 'Surely it won't really 
happen— not in my lifetime, anyway.' But it is happening, here and now. Scientific journals had 
already recorded some 50 species involved in violent dislocations of nature's balance by 1958. 
More examples are being found every year. A recent review of the subject contained references 
to 215 papers reporting or discussing unfavorable upsets in the balance of insect populations 
caused by pesticides. 

Sometimes the result of chemical spraying has been a tremendous upsurge of the very insect 
the spraying was intended to control, as when blackflies in Ontario became 17 times more 
abundant after spraying than they had been before. Or when in England an enormous outbreak 
of the cabbage aphid— an outbreak that had no parallel on record— followed spraying with one 
of the organic phosphorus chemicals. At other times spraying, while reasonably effective 
against the target insect, has let loose a whole Pandora's box of destructive pests that had 
never previously been abundant enough to cause trouble. The spider mite, for example, has 
become practically a worldwide pest as DDT and other insecticides have killed off its enemies. 
The spider mite is not an insect. It is a barely visible eight-legged creature belonging to the 
group that includes spiders, scorpions, and ticks. It has mouth parts adapted for piercing and 
sucking, and a prodigious appetite for the chlorophyll that makes the world green. It inserts 
these minute and stiletto-sharp mouth parts into the outer cells of leaves and evergreen 
needles and extracts the chlorophyll. A mild infestation gives trees and shrubbery a mottled or 
salt-and-pepper appearance; with a heavy mite population, foliage turns yellow and falls. 
This is what happened in some of the western national forests a few years ago, when in 1956 
the United States Forest Service sprayed some 885,000 acres of forested lands with DDT. The 
intention was to control the spruce budworm, but the following summer it was discovered that 
a problem worse than the budworm damage had been created. In surveying the forests from 
the air, vast blighted areas could be seen where the magnificent Douglas firs were turning 
brown and dropping their needles. In the Helena National Forest and on the western slopes of 

the Big Belt Mountains, then in other areas of Montana and down into Ida ho the forests looked 
as though they had been scorched. It was evident that this summer of 1957 had brought the 
most extensive and spectacular infestation of spider mites in history. Almost all of the sprayed 
area was affected. Nowhere else was the damage evident. Searching for precedents, the 
foresters could remember other scourges of spider mites, though less dramatic than this one. 
There had been similar trouble along the Madison River in Yellowstone Park in 1929, in 
Colorado 20 years later, and then in New Mexico in 1956. Each of these outbreaks had followed 
forest spraying with insecticides. (The 1929 spraying, occurring before the DDT era, employed 
lead arsenate.) 

Why does the spider mite appear to thrive on insecticides? Besides the obvious fact that it is 
relatively insensitive to them, there seem to be two other reasons. In nature it is kept in check 
by various predators such as ladybugs, a gall midge, predaceous mites and several pirate bugs, 
all of them extremely sensitive to insecticides. The third reason has to do with population 
pressure within the spider mite colonies. An undisturbed colony of mites is a densely settled 
community, huddled under a protective webbing for concealment from its enemies. When 
sprayed, the colonies disperse as the mites, irritated though not killed by the chemicals, scatter 
out in search of places where they will not be disturbed. In so doing they find a far greater 
abundance of space and food than was available in the former colonies. Their enemies are now 
dead so there is no need for the mites to spend their energy in secreting protective webbing. 
Instead, they pour all their energies into producing more mites. It is not uncommon for their 
egg production to be increased threefold— all through the beneficent effect of insecticides. 
In the Shenandoah Valley of Virginia, a famous apple-growing region, hordes of a small insect 
called the red-banded leaf roller arose to plague the growers as soon as DDT began to replace 
arsenate of lead. Its depredations had never before been important; soon its toll rose to 50 per 
cent of the crop and it achieved the status of the most destructive pest of apples, not only in 
this region but throughout much of the East and Midwest, as the use of DDT increased. The 
situation abounds in ironies. In the apple orchards of Nova Scotia in the late 1940s the worst 
infestations of the codling moth (cause of 'wormy apples') were in the orchards regularly 
sprayed. In unsprayed orchards the moths were not abundant enough to cause real trouble. 
Diligence in spraying had a similarly unsatisfactory reward in the eastern Sudan, where cotton 
growers had a bitter experience with DDT. Some 60,000 acres of cotton were being grown 
under irrigation in the Gash Delta. Early trials of DDT having given apparently good results, 
spraying was intensified. It was then that trouble began. One of the most destructive enemies 
of cotton is the bollworm. But the more cotton was sprayed, the more bollworms appeared. 
The unsprayed cotton suffered less damage to fruits and later to mature bolls than the sprayed, 
and in twice-sprayed fields the yield of seed cotton dropped significantly. Although some of the 
leaf-feeding insects were eliminated, any benefit that might thus have been gained was more 
than offset by bollworm damage. In the end the growers were faced with the unpleasant truth 
that their cotton yield would have been greater had they saved themselves the trouble and 
expense of spraying. 

In the Belgian Congo and Uganda the results of heavy applications of DDT against an insect pest 
of the coffee bush were almost 'catastrophic'. The pest itself was found to be almost 
completely unaffected by the DDT, while its predator was extremely sensitive. In America, 
farmers have repeatedly traded one insect enemy for a worse one as spraying upsets the 

population dynamics of the insect world. Two of the mass-spraying programs recently carried 
out have had precisely this effect. One was the fire ant eradication program in the South; the 
other was the spraying for the Japanese beetle in the Midwest. (See Chapters 10 and 7.) 
When a wholesale application of heptachlor was made to the farmlands in Louisiana in 1957, 
the result was the unleashing of one of the worst enemies of the sugarcane crop— the 
sugarcane borer. Soon after the heptachlor treatment, damage by borers increased sharply. 
The chemical aimed at the fire ant had killed off the enemies of the borer. The crop was so 
severely damaged that farmers sought to bring suit against the state for negligence in not 
warning them that this might happen. The same bitter lesson was learned by Illinois farmers. 
After the devastating bath of dieldrin recently administered to the farmlands in eastern Illinois 
for the control of the Japanese beetle, farmers discovered that corn borers had increased 
enormously in the treated area. In fact, corn grown in fields within this area contained almost 
twice as many of the destructive larvae of this insect as did the corn grown outside. The 
farmers may not yet be aware of the biological basis of what has happened, but they need no 
scientists to tell them they have made a poor bargain. In trying to get rid of one insect, they 
have brought on a scourge of a much more destructive one. According to Department of 
Agriculture estimates, total damage by the Japanese beetle in the United States adds up to 
about 10 million dollars a year, while damage by the corn borer runs to about 85 million. 
It is worth noting that natural forces had been heavily relied on for control of the corn borer. 
Within two years after this insect was accidentally introduced from Europe in 1917, the United 
States Government had mounted one of its most intensive programs for locating and importing 
parasites of an insect pest. Since that time 24 species of parasites of the corn borer have been 
brought in from Europe and the Orient at considerable expense. Of these, 5 are recognized as 
being of distinct value in control. Needless to say, the results of all this work are now 
jeopardized as the enemies of the corn borer are killed off by the sprays. 
If this seems absurd, consider the situation in the citrus groves of California, where the world's 
most famous and successful experiment in biological control was carried out in the 1880s. In 
1872 a scale insect that feeds on the sap of citrus trees appeared in California and within the 
next 25 years developed into a pest so destructive that the fruit crop in many orchards was a 
complete loss. The young citrus industry was threatened with destruction. Many farmers gave 
up and pulled out their trees. Then a parasite of the scale insect was imported from Australia, a 
small lady beetle called the vedalia. Within only two years after the first shipment of the 
beetles, the scale was under complete control throughout the citrus-growing sections of 
California. From that time on one could search for days among the orange groves without 
finding a single scale insect. 

Then in the 1940s the citrus growers began to experiment with glamorous new chemicals 
against other insects. With the advent of DDT and the even more toxic chemicals to follow, the 
populations of the vedalia in many sections of California were wiped out. Its importation had 
cost the government a mere $5000. Its activities had saved the fruit growers several millions of 
dollars a year, but in a moment of heedlessness the benefit was canceled out. Infestations of 
the scale insect quickly reappeared and damage exceeded anything that had been seen for fifty 
years. 'This possibly marked the end of an era,' said Dr. Paul DeBach of the Citrus Experiment 
Station in Riverside. Now control of the scale has become enormously complicated. The vedalia 
can be maintained only by repeated releases and by the most careful attention to spray 

schedules, to minimize their contact with insecticides. And regardless of what the citrus 
growers do, they are more or less at the mercy of the owners of adjacent acreages, for severe 
damage has been done by insecticidal drift. . . . 

All these examples concern insects that attack agricultural crops. What of those that carry 
disease? There have already been warnings. On Nissan Island in the South Pacific, for example, 
spraying had been carried on intensively during the Second World War, but was stopped when 
hostilities came to an end. Soon swarms of a malaria -carrying mosquito reinvaded the island. 
All of its predators had been killed off and there had not been time for new populations to 
become established. The way was therefore clear for a tremendous population explosion. 
Marshall Laird, who has described this incident, compares chemical control to a treadmill; once 
we have set foot on it we are unable to stop for fear of the consequences. 
In some parts of the world disease can be linked with spraying in quite a different way. For 
some reason, snail-like mollusks seem to be almost immune to the effects of insecticides. This 
has been observed many times. In the general holocaust that followed the spraying of salt 
marshes in eastern Florida (pages 115-116), aquatic snails alone survived. The scene as 
described was a macabre picture— something that might have been created by a surrealist 
brush. The snails moved among the bodies of the dead fishes and the moribund crabs, 
devouring the victims of the death rain of poison. But why is this important? It is important 
because many aquatic snails serve as hosts of dangerous parasitic worms that spend part of 
their life cycle in a mollusk, part in a human being. Examples are the blood flukes, or 
schistosoma, that cause serious disease in man when they enter the body by way of drinking 
water or through the skin when people are bathing in infested waters. The flukes are released 
into the water by the host snails. Such diseases are especially prevalent in parts of Asia and 
Africa. Where they occur, insect control measures that favor a vast increase of snails are likely 
to be followed by grave consequences. 

And of course man is not alone in being subject to snail-borne disease. Liver disease in cattle, 
sheep, goats, deer, elk, rabbits, and various other warm-blooded animals may be caused by 
liver flukes that spend part of their life cycles in fresh-water snails. Livers infested with these 
worms are unfit for use as human food and are routinely condemned. Such rejections cost 
American cattlemen about VA million dollars annually. Anything that acts to increase the 
number of snails can obviously make this problem an even more serious one. . . . 
Over the past decade these problems have cast long shadows, but we have been slow to 
recognize them. Most of those best fitted to develop natural controls and assist in putting them 
into effect have been too busy laboring in the more exciting vineyards of chemical control. It 
was reported in 1960 that only 2 per cent of all the economic entomologists in the country 
were then working in the field of biological controls. A substantial number of the remaining 98 
per cent were engaged in research on chemical insecticides. 

Why should this be? The major chemical companies are pouring money into the universities to 
support research on insecticides. This creates attractive fellowships for graduate students and 
attractive staff positions. Biological-control studies, on the other hand, are never so endowed— 
for the simple reason that they do not promise anyone the fortunes that are to be made in the 
chemical industry. These are left to state and federal agencies, where the salaries paid are far 
less. This situation also explains the otherwise mystifying fact that certain outstanding 
entomologists are among the leading advocates of chemical control. Inquiry into the 

background of some of these men reveals that their entire research program is supported by 
the chemical industry. Their professional prestige, sometimes their very jobs depend on the 
perpetuation of chemical methods. Can we then expect them to bite the hand that literally 
feeds them? But knowing their bias, how much credence can we give to their protests that 
insecticides are harmless? Amid the general acclaim for chemicals as the principal method of 
insect control, minority reports have occasionally been filed by those few entomologists who 
have not lost sight of the fact that they are neither chemists nor engineers, but biologists. 
F. H. Jacob in England has declared that 'the activities of many so-called economic 
entomologists would make it appear that they operate in the belief that salvation lies at the 
end of a spray nozzle. ..that when they have created problems of resurgence or resistance or 
mammalian toxicity, the chemist will be ready with another pill. That view is not held 
here. ..Ultimately only the biologist will provide the answers to the basic problems of pest 
control.' 'Economic entomologists must realize,' wrote A. D. Pickett of Nova Scotia, 'that they 
are dealing with living things. ..their work must be more than simply insecticide testing or a 
quest for highly destructive chemicals.' Dr. Pickett himself was a pioneer in the field of working 
out sane methods of insect control that take full advantage of the predatory and parasitic 
species. The method which he and his associates evolved is today a shining model but one too 
little emulated. Only in the integrated control programs developed by some California 
entomologists do we find anything comparable in this country. 

Dr. Pickett began his work some thirty-five years ago in the apple orchards of the Annapolis 
Valley in Nova Scotia, once one of the most concentrated fruit-growing areas in Canada. At that 
time it was believed that insecticides— then inorganic chemicals— would solve the problems of 
insect control, that the only task was to induce fruit growers to follow the recommended 
methods. But the rosy picture failed to materialize. Somehow the insects persisted. New 
chemicals were added, better spraying equipment was devised, and the zeal for spraying 
increased, but the insect problem did not get any better. Then DDT promised to 'obliterate the 
nightmare' of codling moth outbreaks. What actually resulted from its use was an 
unprecedented scourge of mites. 'We move from crisis to crisis, merely trading one problem for 
another,' said Dr. Pickett. 

At this point, however, Dr. Pickett and his associates struck out on a new road instead of going 
along with other entomologists who continued to pursue the will-o'-the-wisp of the ever more 
toxic chemical. Recognizing that they had a strong ally in nature, they devised a program that 
makes maximum use of natural controls and minimum use of insecticides. Whenever 
insecticides are applied only minimum dosages are used— barely enough to control the pest 
without avoidable harm to beneficial species. Proper timing also enters in. Thus, if nicotine 
sulphate is applied before rather than after the apple blossoms turn pink one of the important 
predators is spared, probably because it is still in the egg stage. 

Dr. Pickett uses special care to select chemicals that will do as little harm as possible to insect 
parasites and predators. 'When we reach the point of using DDT, parathion, chlordane, and 
other new insecticides as routine control measures in the same way we have used the inorganic 
chemicals in the past, entomologists interested in biological control may as well throw in the 
sponge,' he says. Instead of these highly toxic, broad-spectrum insecticides, he places chief 
reliance on ryania (derived from ground stems of a tropical plant), nicotine sulphate, and lead 
arsenate. In certain situations very weak concentrations of DDT or malathion are used (1 or 2 

ounces per 100 gallons in contrast to the usual 1 or 2 pounds per 100 gallons). Although these 
two are the least toxic of the modern insecticides, Dr. Pickett hopes by further research to 
replace them with safer and more selective materials. 

How well has this program worked? Nova Scotia orchardists who are following Dr. Pickett's 
modified spray program are producing as high a proportion of first-grade fruit as are those who 
are using intensive chemical applications. They are also getting as good production. They are 
getting these results, moreover, at a substantially lower cost. The outlay for insecticides in Nova 
Scotia apple orchards is only from 10 to 20 per cent of the amount spent in most other apple- 
growing areas. More important than even these excellent results is the fact that the modified 
program worked out by these Nova Scotia n entomologists is not doing violence to nature's 
balance. It is well on the way to realizing the philosophy stated by the Canadian entomologist 
G. C. Ullyett a decade ago: 'We must change our philosophy, abandon our attitude of human 
superiority and admit that in many cases in natural environments we find ways and means of 
limiting populations of organisms in a more economical way than we can do it ourselves.' 

16. The Rumblings of an Avalanche 

IF DARWIN were alive today the insect world would delight and astound him with its 
impressive verification of his theories of the survival of the fittest. Under the stress of intensive 
chemical spraying the weaker members of the insect populations are being weeded out. Now, 
in many areas and among many species only the strong and fit remain to defy our efforts to 
control them. Nearly half a century ago, a professor of entomology at Washington State 
College, A. L. Melander, asked the now purely rhetorical question, 'Can insects become 
resistant to sprays?' If the answer seemed to Melander unclear, or slow in coming, that was 
only because he asked his question too soon— in 1914 instead of 40 years later. In the pre-DDT 
era, inorganic chemicals, applied on a scale that today would seem extraordinarily modest, 
produced here and there strains of insects that could survive chemical spraying or dusting. 
Melander himself had run into difficulty with the San Jose scale, for some years satisfactorily 
controlled by spraying with lime sulfur. Then in the Clarkston area of Washington the insects 
became refractory— they were harder to kill than in the orchards of the Wenatchee and Yakima 
valleys and elsewhere. 

Suddenly the scale insects in other parts of the country seemed to have got the same idea: it 
was not necessary for them to die under the sprayings of lime sulfur, diligently and liberally 
applied by orchardists. Throughout much of the Midwest thousands of acres of fine orchards 
were destroyed by insects now impervious to spraying. Then in California the time-honored 
method of placing canvas tents over trees and fumigating them with hydrocyanic acid began to 
yield disappointing results in certain areas, a problem that led to research at the California 
Citrus Experiment Station, beginning about 1915 and continuing for a quarter of a century. 
Another insect to learn the profitable way of resistance was the codling moth, or appleworm, in 
the 1920s, although lead arsenate had been used successfully against it for some 40 years. 
But it was the advent of DDT and all its many relatives that ushered in the true Age of 
Resistance. It need have surprised no one with even the simplest knowledge of insects or of the 
dynamics of animal populations that within a matter of a very few years an ugly and dangerous 
problem had clearly defined itself. Yet awareness of the fact that insects possess an effective 
counterweapon to aggressive chemical attack seems to have dawned slowly. Only those 
concerned with disease-carrying insects seem by now to have been thoroughly aroused to the 
alarming nature of the situation; the agriculturists still for the most part blithely put their faith 
in the development of new and ever more toxic chemicals, although the present difficulties 
have been born of just such specious reasoning. 

If understanding of the phenomenon of insect resistance developed slowly, it was far otherwise 
with resistance itself. Before 1945 only about a dozen species were known to have developed 
resistance to any of the pre-DDT insecticides. With the new organic chemicals and new 
methods for their intensive application, resistance began a meteoric rise that reached the 
alarming level of 137 species in 1960. No one believes the end is in sight. More than 1000 
technical papers have now been published on the subject. The World Health Organization has 
enlisted the aid of some 300 scientists in all parts of the world, declaring that 'resistance is at 
present the most important single problem facing vector-control programmes.' A distinguished 

British student of animal populations, Dr. Charles Elton, has said, 'We are hearing the early 
rumblings of what may become an avalanche in strength.' 

Sometimes resistance develops so rapidly that the ink is scarcely dry on a report hailing 
successful control of a species with some specified chemical when an amended report has to be 
issued. In South Africa, for example, cattlemen had long been plagued by the blue tick, from 
which, on one ra nch alone, 600 head of cattle had died in one year. The tick had for some years 
been resistant to arsenical dips. Then benzene hexachloride was tried, and for a very short time 
all seemed to be well. Reports issued early in the year 1949 declared that the arsenic-resistant 
ticks could be controlled readily with the new chemical; later in the same year, a bleak notice of 
developing resistance had to be published. The situation prompted a writer in the Leather 
Trades Review to comment in 1950: 'News such as this quietly trickling through scientific circles 
and appearing in small sections of the overseas press is enough to make headlines as big as 
those concerning the new atomic bomb if only the significance of the matter were properly 
understood.' Although insect resistance is a matter of concern in agriculture and forestry, it is in 
the field of public health that the most serious apprehensions have been felt. The relation 
between various insects and many diseases of man is an ancient one. Mosquitoes of the genus 
Anopheles may inject into the human bloodstream the single-celled organism of malaria. 
Other mosquitoes transmit yellow fever. Still others carry encephalitis. The housefly, which 
does not bite, nevertheless by contact may contaminate human food with the bacillus of 
dysentery, and in many parts of the world may play an important part in the transmission of 
eye diseases. The list of diseases and their insect carriers, or vectors, includes typhus and body 
lice, plague and rat fleas, African sleeping sickness and tsetse flies, various fevers and ticks, and 
innumerable others. 

These are important problems and must be met. No responsible person contends that insect- 
borne disease should be ignored. The question that has now urgently presented itself is 
whether it is either wise or responsible to attack the problem by methods that are rapidly 
making it worse. The world has heard much of the triumphant war against disease through the 
control of insect vectors of infection, but it has heard little of the other side of the story— the 
defeats, the short-lived triumphs that now strongly support the alarming view that the insect 
enemy has been made actually stronger by our efforts. Even worse, we may have destroyed our 
very means of fighting. A distinguished Canadian entomologist, Dr. A. W. A. Brown, was 
engaged by the World Health Organization to make a comprehensive survey of the resistance 
problem. In the resulting monograph, published in 1958, Dr. Brown has this to say: 'Barely a 
decade after the introduction of the potent synthetic insecticides in public health programmes, 
the main technical problem is the development of resistance to them by the insects they 
formerly controlled.' In publishing his monograph, the World Health Organization warned that 
'the vigorous offensive now being pursued against arthropodborne diseases such as malaria, 
typhus fever, and plague risks a serious setback unless this new problem can be rapidly 

What is the measure of this setback? The list of resistant species now includes practically all of 
the insect groups of medical importance. Apparently the blackflies, sand flies, and tsetse flies 
have not yet become resistant to chemicals. On the other hand, resistance among houseflies 
and body lice has now developed on a global scale. Malaria programs are threatened by 
resistance among mosquitoes. The oriental rat flea, the principal vector of plague, has recently 

demonstrated resistance to DDT, a most serious development. Countries reporting resistance 
among a large number of other species represent every continent and most of the island 

Probably the first medical use of modern insecticides occurred in Italy in 1943 when the Allied 
Military Government launched a successful attack on typhus by dusting enormous numbers of 
people with DDT. This was followed two years later by extensive application of residual sprays 
for the control of malaria mosquitoes. Only a year later the first signs of trouble appeared. Both 
houseflies and mosquitoes of the genus Culex began to show resistance to the sprays. In 1948 a 
new chemical, chlordane, was tried as a supplement to DDT. This time good control was 
obtained for two years, but by August of 1950 chlordane-resistant flies appeared, and by the 
end of that year all of the houseflies as well as the Culex mosquitoes seemed to be resistant to 
chlordane. As rapidly as new chemicals were brought into use, resistance developed. 
By the end of 1951, DDT, methoxychlor, chlordane, heptachlor, and benzene hexachloride had 
joined the list of chemicals no longer effective. The flies, meanwhile, had become 'fantastically 
abundant'. The same cycle of events was being repeated in Sardinia during the late 1940s. In 
Denmark, products containing DDT were first used in 1944; by 1947 fly control had failed in 
many places. In some areas of Egypt, flies had already become resistant to DDT by 1948; BHC 
was substituted but was effective for less than a year. One Egyptian village in particular 
symbolizes the problem. Insecticides gave good control of flies in 1950 and during this same 
year the infant mortality rate was reduced by nearly 50 per cent. The next year, nevertheless, 
flies were resistant to DDT and chlordane. The fly population returned to its former level; so did 
infant mortality. 

In the United States, DDT resistance among flies had become widespread in the Tennessee 
Valley by 1948. Other areas followed. Attempts to restore control with dieldrin met with little 
success, for in some places the flies developed strong resistance to this chemical within only 
two months. After running through all the available chlorinated hydrocarbons, control agencies 
turned to the organic phosphates, but here again the story of resistance was repeated. The 
present conclusion of experts is that 'housefly control has escaped insecticidal techniques and 
once more must be based on general sanitation.' The control of body lice in Naples was one of 
the earliest and most publicized achievements of DDT. During the next few years its success in 
Italy was matched by the successful control of lice affecting some two million people in Japan 
and Korea in the winter of 1945-46. Some premonition of trouble ahead might have been 
gained by the failure to control a typhus epidemic in Spain in 1948. Despite this failure in actual 
practice, encouraging laboratory experiments led entomologists to believe lice were unlikely to 
develop resistance. Events in Korea in the winter of 1950-51 were therefore startling. When 
DDT powder was applied to a group of Korean soldiers the extraordinary result was an actual 
increase in the infestation of lice. When lice were collected and tested, it was found that 5 per 
cent DDT powder caused no increase in their natural mortality rate. Similar results among lice 
collected from vagrants in Tokyo, from an asylum in Itabashi, and from refugee camps in Syria, 
Jordan, and eastern Egypt, confirmed the ineffectiveness of DDT for the control of lice and 
typhus. When by 1957 the list of countries in which lice had become resistant to DDT was 
extended to include Iran, Turkey, Ethiopia, West Africa, South Africa, Peru, Chile, France, 
Yugoslavia, Afghanistan, Uganda, Mexico, and Tanganyika, the initial triumph in Italy seemed 
dim indeed. The first malaria mosquito to develop resistance to DDT was Anopheles sacharovi 

in Greece. Extensive spraying was begun in 1946 with early success; by 1949, however, 
observers noticed that adult mosquitoes were resting in large numbers under road bridges, 
although they were absent from houses and stables that had been treated. Soon this habit of 
outside resting was extended to caves, outbuildings, and culverts and to the foliage and trunks 
of orange trees. Apparently the adult mosquitoes had become sufficiently tolerant of DDT to 
escape from sprayed buildings and rest and recover in the open. A few months later they were 
able to remain in houses, where they were found resting on treated walls. This was a portent of 
the extremely serious situation that has now developed. Resistance to insecticides by 
mosquitoes of the anophelene group has surged upward at an astounding rate, being created 
by the thoroughness of the very housespraying programs designed to eliminate malaria. In 
1956, only 5 species of these mosquitoes displayed resistance; by early 1960 the number had 
risen from 5 to 28! The number includes very dangerous malaria vectors in West Africa, the 
Middle East, Central America, Indonesia, and the eastern European region. 
Among other mosquitoes, including carriers of other diseases, the pattern is being repeated. A 
tropical mosquito that carries parasites responsible for such diseases as elephantiasis has 
become strongly resistant in many parts of the world. In some areas of the United States the 
mosquito vector of western equine encephalitis has developed resistance. An even more 
serious problem concerns the vector of yellow fever, for centuries one of the great plagues of 
the world. Insecticide resistant strains of this mosquito have occurred in Southeast Asia and are 
now common in the Caribbean region. The consequences of resistance in terms of malaria and 
other diseases are indicated by reports from many parts of the world. An outbreak of yellow 
fever in Trinidad in 1954 followed failure to control the vector mosquito because of resistance. 
There has been a flare-up of malaria in Indonesia and Iran. In Greece, Nigeria, and Liberia the 
mosquitoes continue to harbor and transmit the malaria parasite. A reduction of diarrheal 
disease achieved in Georgia through fly control was wiped out within about a year. The 
reduction in acute conjunctivitis in Egypt, also attained through temporary fly control, did not 
last beyond 1950. 

Less serious in terms of human health, but vexatious as man measures economic values, is the 
fact that salt-marsh mosquitoes in Florida also are showing resistance. Although these are not 
vectors of disease, their presence in bloodthirsty swarms had rendered large areas of coastal 
Florida uninhabitable until control— of an uneasy and temporary nature— was established. But 
this was quickly lost. The ordinary house mosquito is here and there developing resistance, a 
fact that should give pause to many communities that now regularly arrange for wholesale 
spraying. This species is now resistant to several insecticides, among which is the almost 
universally used DDT, in Italy, Israel, Japan, France, and parts of the United States, including 
California, Ohio, New Jersey, and Massachusetts. 

Ticks are another problem. The woodtick, vector of spotted fever, has recently developed 
resistance; in the brown dog tick the ability to escape a chemical death has long been 
thoroughly and widely established. This poses problems for human beings as well as for dogs. 
The brown dog tick is a semitropical species and when it occurs as far north as New Jersey it 
must live over winter in heated buildings rather than out of doors. John C. Pa Mister of the 
American Museum of Natural History reported in the summer of 1959 that his department had 
been getting a number of calls from neighboring apartments on Central Park West. 'Every now 
and then,' Mr. Pallister said, 'a whole apartment house gets infested with young ticks, and 

they're hard to get rid of. A dog will pick up ticks in Central Park, and then the ticks lay eggs and 
they hatch in the apartment. They seem immune to DDT or chlordane or most of our modern 
sprays. It used to be very unusual to have ticks in New York City, but now they're all over here 
and on Long Island, in Westchester and on up into Connecticut. We've noticed this particularly 
in the past five or six years.' 

The German cockroach throughout much of North America has become resistant to chlordane, 
once the favorite weapon of exterminators who have now turned to the organic phosphates. 
However, the recent development of resistance to these insecticides confronts the 
exterminators with the problem of where to go next. Agencies concerned with vector-borne 
disease are at present coping with their problems by switching from one insecticide to another 
as resistance develops. But this cannot go on indefinitely, despite the ingenuity of the chemists 
in supplying new materials. Dr. Brown has pointed out that we are traveling 'a one-way street'. 
No one knows how long the street is. If the dead end is reached before control of disease- 
carrying insects is achieved, our situation will indeed be critical. 

With insects that infest crops the story is the same. To the list of about a dozen agricultural 
insects showing resistance to the inorganic chemicals of an earlier era there is now added a 
host of others resistant to DDT, BHC, lindane, toxaphene, dieldrin, aldrin, and even to the 
phosphates from which so much was hoped. The total number of resistant species among crop- 
destroying insects had reached 65 in 1960. The first cases of DDT resistance among agricultural 
insects appeared in the United States in 1951, about six years after its first use. Perhaps the 
most troublesome situation concerns the codling moth, which is now resistant to DDT in 
practically all of the world's apple-growing regions. Resistance in cabbage insects is creating 
another serious problem. Potato insects are escaping chemical control in many sections of the 
United States. Six species of cotton insects, along with an assortment of thrips, fruit moths, leaf 
hoppers, caterpillars, mites, aphids, wireworms, and many others now are able to ignore the 
farmer's assault with chemical sprays. 

The chemical industry is perhaps understandably loath to face up to the unpleasant fact of 
resistance. Even in 1959, with more than 100 major insect species showing definite resistance 
to chemicals, one of the leading journals in the field of agricultural chemistry spoke of 'real or 
imagined' insect resistance. Yet hopefully as the industry may turn its face the other way, the 
problem simply does not go away, and it presents some unpleasant economic facts. One is that 
the cost of insect control by chemicals is increasing steadily. It is no longer possible to stockpile 
materials well in advance; what today may be the most promising of insecticidal chemicals may 
be the dismal failure of tomorrow. The very substantial financial investment involved in backing 
and launching an insecticide may be swept away as the insects prove once more that the 
effective approach to nature is not through brute force. And however rapidly technology may 
invent new uses for insecticides and new ways of applying them, it is likely to find the insects 
keeping a lap ahead. . . . 

Darwin himself could scarcely have found a better example of the operation of natural selection 
than is provided by the way the mechanism of resistance operates. Out of an original 
population, the members of which vary greatly in qualities of structure, behavior, or physiology, 
it is the 'tough' insects that survive chemical attack. Spraying kills off the weaklings. The only 
survivors are insects that have some inherent quality that allows them to escape harm. These 
are the parents of the new generation, which, by simple inheritance, possesses all the qualities 

of 'toughness' inherent in its forebears. Inevitably it follows that intensive spraying with 
powerful chemicals only makes worse the problem it is designed to solve. After a few 
generations, instead of a mixed population of strong and weak insects, there results a 
population consisting entirely of tough, resistant strains. 

The means by which insects resist chemicals probably vary and as yet are not thoroughly 
understood. Some of the insects that defy chemical control are thought to be aided by a 
structural advantage, hut there seems to be little actual proof of this. That immunity exists in 
some strains is clear, however, from observations like those of Dr. Briejer, who reports 
watching flies at the Pest Control Institute at Springforbi, Denmark, 'disporting themselves in 
DDT as much at home as primitive sorcerers cavorting over red-hot coals.' Similar reports come 
from other parts of the world. In Malaya, at Kuala Lumpur, mosquitoes at first reacted to DDT 
by leaving the treated interiors. As resistance developed, however, they could be found at rest 
on surfaces where the deposit of DDT beneath them was clearly visible by torchlight. And in an 
army camp in southern Taiwan samples of resistant bedbugs were found actually carrying a 
deposit of DDT powder on their bodies. When these bedbugs were experimentally placed in 
cloth impregnated with DDT, they lived for as long as a month; they proceeded to lay their 
eggs; and the resulting young grew and thrived. 

Nevertheless, the quality of resistance does not necessarily depend on physical structure. DDT- 
resistant flies possess an enzyme that allows them to detoxify the insecticide to the less toxic 
chemical DDE. This enzyme occurs only in flies that possess a genetic factor for DDT resistance. 
This factor is, of course, hereditary. How flies and other insects detoxify the organic phosphorus 
chemicals is less clearly understood. Some behavioral habit may also place the insect out of 
reach of chemicals. Many workers have noticed the tendency of resistant flies to rest more on 
untreated horizontal surfaces than on treated walls. Resistant houseflies may have the stable- 
fly habit of sitting still in one place, this greatly reducing the frequency of their contact with 
residues of poison. Some malaria mosquitoes have a habit that so reduces their exposure to 
DDT as to make them virtually immune. Irritated by the spray, they leave the huts and survive 
outside. Ordinarily resistance takes two or three years to develop, although occasionally it will 
do so in only one season, or even less. At the other extreme it may take as long as six years. The 
number of generations produced by an insect population in a year is important, and this varies 
with species and climate. Flies in Canada, for example, have been slower to develop resistance 
than those in southern United States, where long hot summers favor a rapid rate of 

The hopeful question is sometimes asked, 'If insects can become resistant to chemicals, could 
human beings do the same thing?' Theoretically they could; but since this would take hundreds 
or even thousands of years, the comfort to those living now is slight. Resistance is not 
something that develops in an individual. If he possesses at birth some qualities that make him 
less susceptible than others to poisons he is more likely to survive and produce children. 
Resistance, therefore, is something that develops in a population after time measured in 
several or many generations. Human populations reproduce at the rate of roughly three 
generations per century, but new insect generations arise in a matter of days or weeks. 
'It is more sensible in some cases to take a small amount of damage in preference to having 
one for a time but paying for it in the long run by losing the very means of fighting,' is the 
advice given in Holland by Dr. Briejer in his capacity as director of the Plant Protection Service. 

'Practical advice should be "Spray as little as you possibly can" rather than "Spray to the limit of 
your capacity.". ..Pressure on the pest population should always be as slight as possible.' 
Unfortunately, such vision has not prevailed in the corresponding agricultural services of the 
United States. The Department of Agriculture's Yearbook for 1952, devoted entirely to insects, 
recognizes the fact that insects become resistant but says, 'More applications or greater 
quantities of the insecticides are needed then for adequate control.' The Department does not 
say what will happen when the only chemicals left untried are those that render the earth not 
only insectless but lifeless. But in 1959, only seven years after this advice was given, a 
Connecticut entomologist was quoted in the Journal of Agricultural and Food Chemistry to the 
effect that on at least one or two insect pests the last available new material was then being 
used. Dr. Briejer says: It is more than clear that we are traveling a dangerous road. ...We are 
going to have to do some very energetic research on other control measures, measures that will 
have to be biological, not chemical. Our aim should be to guide natural processes as cautiously 
as possible in the desired direction rather than to use brute force... 

We need a more high-minded orientation and a deeper insight, which I miss in many 
researchers. Life is a miracle beyond our comprehension, and we should reverence it even 
where we have to struggle against it. ..The resort to weapons such as insecticides to control it is 
a proof of insufficient knowledge and of an incapacity so to guide the processes of nature that 
brute force becomes unnecessary. Humbleness is in order; there is no excuse for scientific 
conceit here. 

17. The Other Road 

WE STAND NOW where two roads diverge. But unlike the roads in Robert Frost's 
familiar poem, they are not equally fair. The road we have long been traveling is deceptively 
easy, a smooth superhighway on which we progress with great speed, but at its end lies 
disaster. The other fork of the road— the one 'less traveled by'— offers our last, our only chance 
to reach a destination that assures the preservation of our earth. 

The choice, after all, is ours to make. If, having endured much, we have at last asserted our 
'right to know', and if, knowing, we have concluded that we are being asked to take senseless 
and frightening risks, then we should no longer accept the counsel of those who tell us that we 
must fill our world with poisonous chemicals; we should look about and see what other course 
is open to us. A truly extraordinary variety of alternatives to the chemical control of insects is 
available. Some are already in use and have achieved brilliant success. Others are in the stage 
of laboratory testing. Still others are little more than ideas in the minds of imaginative 
scientists, waiting for the opportunity to put them to the test. All have this in common: they are 
biological solutions, based on understanding of the living organisms they seek to control, and of 
the whole fabric of life to which these organisms belong. Specialists representing various areas 
of the vast field of biology are contributing— entomologists, pathologists, geneticists, 
physiologists, biochemists, ecologists— all pouring their knowledge and their creative 
inspirations into the formation of a new science of biotic controls. 

'Any science may be likened to a river,' says a Johns Hopkins biologist, Professor Carl P. 
Swanson. 'It has its obscure and unpretentious beginning; its quiet stretches as well as its 
rapids; its periods of drought as well as of fullness. It gathers momentum with the work of 
many investigators and as it is fed by other streams of thought; it is deepened and broadened 
by the concepts and generalizations that are gradually evolved.' 

So it is with the science of biological control in its modern sense. In America it had its obscure 
beginnings a century ago with the first attempts to introduce natural enemies of insects that 
were proving troublesome to farmers, an effort that sometimes moved slowly or not at all, but 
now and again gathered speed and momentum under the impetus of an outstanding success. It 
had its period of drought when workers in applied entomology, dazzled by the spectacular new 
insecticides of the 1940s, turned their backs on all biological methods and set foot on 'the 
treadmill of chemical control'. But the goal of an insect-free world continued to recede. Now at 
last, as it has become apparent that the heedless and unrestrained use of chemicals is a greater 
menace to ourselves than to the targets, the river which is the science of biotic control flows 
again, fed by new streams of thought. 

Some of the most fascinating of the new methods are those that seek to turn the strength of a 
species against itself— to use the drive of an insect's life forces to destroy it. The most 
spectacular of these approaches is the 'male sterilization' technique developed by the chief of 
the United States Department of Agriculture's Entomology Research Branch, Dr. Edward 
Knipling, and his associates. About a quarter of a century ago Dr. Knipling startled his colleagues 
by proposing a unique method of insect control. If it were possible to sterilize and release large 
numbers of insects, he theorized, the sterilized males would, under certain conditions, compete 

with the normal wild males so successfully that, after repeated releases, only infertile eggs 
would be produced and the population would die out. 

The proposal was met with bureaucratic inertia and with skepticism from scientists, but the 
idea persisted in Dr. Knipling's mind. One major problem remained to be solved before it could 
be put to the test— a practical method of insect sterilization had to be found. Academically, the 
fact that insects could be sterilized by exposure to X-ray had been known since 1916, when an 
entomologist by the name of G. A. Runner reported such sterilization of cigarette beetles. 
Hermann Muller's pioneering work on the production of mutations by X-ray opened up vast 
new areas of thought in the late 1920s, and by the middle of the century various workers had 
reported the sterilization by X-rays or gamma rays of at least a dozen species of insects. 
But these were laboratory experiments, still a long way from practical application. About 1950, 
Dr. Knipling launched a serious effort to turn insect sterilization into a weapon that would wipe 
out a major insect enemy of livestock in the South, the screw-worm fly. The females of this 
species lay their eggs in any open wound of a warm-blooded animal. The hatching larvae are 
parasitic, feeding on the flesh of the host. A full-grown steer may succumb to a heavy 
infestation in 10 days, and livestock losses in the United States have been estimated at 
$40,000,000 a year. The toll of wildlife is harder to measure, but it must be great. Scarcity of 
deer in some areas of Texas is attributed to the screw-worm. This is a tropical or sub-tropical 
insect, inhabiting South and Central America and Mexico, and in the United States normally 
restricted to the Southwest. About 1933, however, it was accidentally introduced into Florida, 
where the climate allowed it to survive over winter and to establish populations. It even pushed 
into southern Alabama and Georgia, and soon the livestock industry of the southeastern states 
was faced with annual losses running to $20,000,000. 

A vast amount of information on the biology of the screw-worm had been accumulated over 
the years by Agriculture Department scientists in Texas. By 1954, after some preliminary field 
trials on Florida islands, Dr. Knipling was ready for a full-scale test of his theory. For this, by 
arrangement with the Dutch Government, he went to the island of Curacao in the Caribbean, 
cut off from the mainland by at least 50 miles of sea. Beginning in August 1954, screw-worms 
reared and sterilized in an Agriculture Department laboratory in Florida were flown to Curacao 
and released from airplanes at the rate of about 400 per square mile per week. Almost at once 
the number of egg masses deposited on experimental goats began to decrease, as did their 
fertility. Only seven weeks after the releases were started, all eggs were infertile. Soon it was 
impossible to find a single egg mass, sterile or otherwise. The screw-worm had indeed been 
eradicated on Curacao. The resounding success of the Curacao experiment whetted the 
appetites of Florida livestock raisers for a similar feat that would relieve them of the scourge of 
screw-worms. Although the difficulties here were relatively enormous— an area 300 times as 
large as the small Caribbean island— in 1957 the United States Department of Agriculture and 
the State of Florida joined in providing funds for an eradication effort. The project involved the 
weekly production of about 50 million screw-worms at a specially constructed 'fly factory', the 
use of 20 light airplanes to fly prearranged flight patterns, five to six hours daily, each plane 
carrying a thousand paper cartons, each carton containing 200 to 400 irradiated flies. 
The cold winter of 1957-58, when freezing temperatures gripped northern Florida, gave an 
unexpected opportunity to start the program while the screw-worm populations were reduced 
and confined to a small area. By the time the program was considered complete at the end of 

17 months, 3Vi billion artificially reared, sterilized flies had been released over Florida and 
sections of Georgia and Alabama. The last-known animal wound infestation that could be 
attributed to screwworms occurred in February 1959. In the next few weeks several adults 
were taken in traps. Thereafter no trace of the screwworm could be discovered. Its extinction in 
the Southeast had been accomplished— a triumphant demonstration of the worth of scientific 
creativity, aided by thorough basic research, persistence, and determination. 
Now a quarantine barrier in Mississippi seeks to prevent the re-entrance of the screw-worm 
from the Southwest, where it is firmly entrenched. Eradication there would be a formidable 
undertaking, considering the vast areas involved and the probability of re-invasion from 
Mexico. Nevertheless, the stakes are high and the thinking in the Department seems to be that 
some sort of program, designed at least to hold the screw-worm populations at very low levels, 
may soon be attempted in Texas and other infested areas of the Southwest. . . . 
The brilliant success of the screw-worm campaign has stimulated tremendous interest in 
applying the same methods to other insects. Not all, of course, are suitable subjects for this 
technique, much depending on details of the life history, population density, and reactions to 
radiation. Experiments have been undertaken by the British in the hope that the method could 
be used against the tsetse fly in Rhodesia. This insect infests about a third of Africa, posing a 
menace to human health and preventing the keeping of livestock in an area of some AVi million 
square miles of wooded grasslands. The habits of the tsetse differ considerably from those of 
the screw-worm fly, and although it can be sterilized by radiation some technical difficulties 
remain to be worked out before the method can be applied. 

The British have already tested a large number of other species for susceptibility to radiation. 
United States scientists have had some encouraging early results with the melon fly and the 
oriental and Mediterranean fruit flies in laboratory tests in Hawaii and field tests on the remote 
island of Rota. The corn borer and the sugarcane borer are also being tested. There are 
possibilities, too, that insects of medical importance might be controlled by sterilization. A 
Chilean scientist has pointed out that ma I aria -carrying mosquitoes persist in his country in spite 
of insecticide treatment; the release of sterile males might then provide the final blow needed 
to eliminate this population. 

The obvious difficulties of sterilizing by radiation have led to search for an easier method of 
accomplishing similar results, and there is now a strongly running tide of interest in chemical 
sterilants. Scientists at the Department of Agriculture laboratory in Orlando, Florida, are now 
sterilizing the housefly in laboratory experiments and even in some field trials, using chemicals 
incorporated in suitable foods. In a test on an island in the Florida Keys in 1961, a population of 
flies was nearly wiped out within a period of only five weeks. Repopulation of course followed 
from nearby islands, but as a pilot project the test was successful. The Department's 
excitement about the promise of this method is easily understood. In the first place, as we have 
seen, the housefly has now become virtually uncontrollable by insecticides. A completely new 
method of control is undoubtedly needed. One of the problems of sterilization by radiation is 
that this requires not only artificial rearing but the release of sterile males in larger number 
than are present in the wild population. This could be done with the screw-worm, which is 
actually not an abundant insect. With the housefly, however, more than doubling the 
population through releases could be highly objectionable, even though the increase would be 
only temporary. A chemical sterilant, on the other hand, could be combined with a bait 

substance and introduced into the natural environment of the fly; insects feeding on it would 
become sterile and in the course of time the sterile flies would predominate and the insects 
would breed themselves out of existence. The testing of chemicals for a sterilizing effect is 
much more difficult than the testing of chemical poisons. It takes 30 days to evaluate one 
chemical— although, of course, a number of tests can be run concurrently. Yet between April 
1958 and December 1961 several hundred chemicals were screened at the Orlando laboratory 
for a possible sterilizing effect. 

The Department of Agriculture seems happy to have found among these even a handful of 
chemicals that show promise. Now other laboratories of the Department are taking up the 
problem, testing chemicals against stable flies, mosquitoes, boll weevils, and an assortment of 
fruit flies. All this is presently experimental but in the few years since work began on 
chemosterilants the project has grown enormously. In theory it has many attractive features. 
Dr. Knipling has pointed out that effective chemical insect sterilization 'might easily outdo some 
of the best of known insecticides.' Take an imaginary situation in which a population of a 
million insects is multiplying five times in each generation. An insecticide might kill 90 per cent 
of each generation, leaving 125,000 insects alive after the third generation. In contrast, a 
chemical that would produce 90 per cent sterility would leave only 125 insects alive. 
On the other side of the coin is the fact that some extremely potent chemicals are involved. It is 
fortunate that at least during these early stages most of the men working with chemosterilants 
seem mindful of the need to find safe chemicals and safe methods of application. Nonetheless, 
suggestions are heard here and there that these sterilizing chemicals might be applied as aerial 
sprays— for example, to coat the foliage chewed by gypsy moth larvae. To attempt any such 
procedure without thorough advance research on the hazards involved would be the height of 
irresponsibility. If the potential hazards of the chemosterilants are not constantly borne in mind 
we could easilyfind ourselves in even worse trouble than that now created by the insecticides. 
The sterilants currently being tested fall generally into two groups, both of which are extremely 
interesting in their mode of action. The first are intimately related to the life processes, or 
metabolism, of the cell; i.e., they so closely resemble a substance the cell or tissue needs that 
the organism 'mistakes' them for the true metabolite and tries to incorporate them in its 
normal building processes. But the fit is wrong in some detail and the process comes to a halt. 
Such chemicals are called antimetabolites. 

The second group consists of chemicals that act on the chromosomes, probably affecting the 
gene chemicals and causing the chromosomes to break up. The chemosterilants of this group 
are alkylating agents, which are extremely reactive chemicals, capable of intense cell 
destruction, damage to chromosomes, and production of mutations. It is the view of Dr. Peter 
Alexander of the Chester Beatty Research Institute in London that 'any alkylating agent which is 
effective in sterilizing insects would also be a powerful mutagen and carcinogen.' Dr. Alexander 
feels that any conceivable use of such chemicals in insect control would be 'open to the most 
severe objections'. It is to be hoped, therefore, that the present experiments will lead not to 
actual use of these particular chemicals but to the discovery of others that will be safe and also 
highly specific in their action on the target insect. . . . 

Some of the most interesting of the recent work is concerned with still other ways of forging 
weapons from the insect's own life processes. Insects produce a variety of venoms, attractants, 
repellents. What is the chemical nature of these secretions? Could we make use of them as, 

perhaps, very selective insecticides? Scientists at Cornell University and elsewhere are trying to 
find answers to some of these questions, studying the defense mechanisms by which many 
insects protect themselves from attack by predators, working out the chemical structure of 
insect secretions. Other scientists are working on the so-called 'juvenile hormone', a powerful 
substance which prevents metamorphosis of the larval insect until the proper stage of growth 
has been reached. 

Perhaps the most immediately useful result of this exploration of insect secretion is the 
development of lures, or attractants. Here again, nature has pointed the way. The gypsy moth 
is an especially intriguing example. The female moth is too heavy-bodied to fly. She lives on or 
near the ground, fluttering about among low vegetation or creeping up tree trunks. The male, 
on the contrary, is a strong flier and is attracted even from considerable distances by a scent 
released by the female from special glands. Entomologists have taken advantage of this fact for 
a good many years, laboriously preparing this sex attractant from the bodies of the female 
moths. It was then used in traps set for the males in census operations along the fringe of the 
insect's range. But this was an extremely expensive procedure. Despite the much publicized 
infestations in the northeastern states, there were not enough gypsy moths to provide the 
material, and handcollected female pupae had to be imported from Europe, sometimes at a 
cost of half a dollar per tip. It was a tremendous breakthrough, therefore, when, after years of 
effort, chemists of the Agriculture Department recently succeeded in isolating the attractant. 
Following upon this discovery was the successful preparation of a closely related synthetic 
material from a constituent of castor oil; this not only deceives the male moths but is 
apparently fully as attractive as the natural substance. 

As little as one microgram (1/1,000,000 gram) in a trap is an effective lure. All this is of much 
more than academic interest, for the new and economical 'gyplure' might be used not merely in 
census operations but in control work. Several of the more attractive possibilities are now being 
tested. In what might be termed an experiment in psychological warfare, the attractant is 
combined with a granular material and distributed by planes. The aim is to confuse the male 
moth and alter the normal behavior so that, in the welter of attractive scents, he cannot find 
the true scent trail leading to the female. This line of attack is being carried even further in 
experiments aimed at deceiving the male into attempting to mate with a spurious female. In 
the laboratory, male gypsy moths have attempted copulation with chips of wood, vermiculite, 
and other small, inanimate objects, so long as they were suitably impregnated with gyplure. 
Whether such diversion of the mating instinct into nonproductive channels would actually serve 
to reduce the population remains to be tested, but it is an interesting possibility. 
The gypsy moth lure was the first insect sex attractant to be synthesized, but probably there 
will soon be others. A number of agricultural insects are being studied for possible attractants 
that man could imitate. Encouraging results have been obtained with the Hessian fly and the 
tobacco hornworm. Combinations of attractants and poisons are being tried against several 
insect species. Government scientists have developed an attractant called methyl-eugenol, 
which males of the oriental fruit fly and the melon fly find irresistible. This has been combined 
with a poison in tests in the Bonin Islands 450 miles south of Japan. Small pieces of fiberboard 
were impregnated with the two chemicals and were distributed by air over the entire island 
chain to attract and kill the male flies. This program of 'male annihilation' was begun in 1960: a 
year later the Agriculture Department estimated that more than 99 per cent of the population 

had been eliminated. The method as here applied seems to have marked advantages over the 
conventional broadcasting of insecticides. The poison, an organic phosphorus chemical, is 
confined to squares of fiberboard which are unlikely to be eaten by wildlife; its residues, 
moreover, are quickly dissipated and so are not potential contaminants of soil or water. 
But not all communication in the insect world is by scents that lure or repel. Sound also may be 
a warning or an attraction. The constant stream of ultrasonic sound that issues from a bat in 
flight (serving as a radar system to guide it through darkness) is heard by certain moths, 
enabling them to avoid capture. The wing sounds of approaching parasitic flies warn the larvae 
of some sawflies to herd together for protection. On the other hand, the sounds made by 
certain wood-boring insects enable their parasites to find them, and to the male mosquito the 
wingbeat of the female is a siren song. 

What use, if any, can be made of this ability of the insect to detect and react to sound? As yet in 
the experimental stage, but nonetheless interesting, is the initial success in attracting male 
mosquitoes to playback recordings of the flight sound of the female. The males were lured to a 
charged grid and so killed. The repellent effect of bursts of ultrasonic sound is being tested in 
Canada against corn borer and cutworm moths. Two authorities on animal sound, Professors 
Hubert and Mable Frings of the University of Hawaii, believe that a field method of influencing 
the behavior of insects with sound only awaits discovery of the proper key to unlock and apply 
the vast existing knowledge of insect sound production and reception. Repellent sounds may 
offer greater possibilities than attractants. The Fringses are known for their discovery that 
starlings scatter in alarm before a recording of the distress cry of one of their fellows; perhaps 
somewhere in this fact is a central truth that may be applied to insects. To practical men of 
industry the possibilities seem real enough so that at least one major electronic corporation is 
preparing to set up a laboratory to test them. 

Sound is also being tested as an agent of direct destruction. Ultrasonic sound will kill all 
mosquito larvae in a laboratory tank; however, it kills other aquatic organisms as well. In other 
experiments, blowflies, mealworms, and yellow fever mosquitoes have been killed by airborne 
ultrasonic sound in a matter of seconds. All such experiments are first steps toward wholly new 
concepts of insect control which the miracles of electronics may some day make a reality. . . . 
The new biotic control of insects is not wholly a matter of electronics and gamma radiation and 
other products of man's inventive mind. Some of its methods have ancient roots, based on the 
knowledge that, like ourselves, insects are subject to disease. Bacterial infections sweep 
through their populations like the plagues of old; under the onset of a virus their hordes sicken 
and die. The occurrence of disease in insects was known before the time of Aristotle; the 
maladies of the silkworm were celebrated in medieval poetry; and through study of the 
diseases of this same insect the first understanding of the principles of infectious disease came 
to Pasteur. Insects are beset not only by viruses and bacteria but also by fungi, protozoa, 
microscopic worms, and other beings from all that unseen world of minute life that, by and 
large, befriends mankind. For the microbes include not only disease organisms but those that 
destroy waste matter, make soils fertile, and enter into countless biological processes like 
fermentation and nitrification. Why should they not also aid us in the control of insects? One of 
the first to envision such use of microorganisms was the 19th-century zoologist Elie 
Metchnikoff. During the concluding decades of the 19th and the first half of the 20th centuries 
the idea of microbial control was slowly taking form. The first conclusive proof that an insect 

could be brought under control by introducing a disease into its environment came in the late 
1930s with the discovery and use of milky disease for the Japanese beetle, which is caused by 
the spores of a bacterium belonging to the genus Bacillus. This classic example of bacterial 
control has a long history of use in the eastern part of the United States, as I have pointed out 
i n Chapter 7. 

High hopes now attend tests of another bacterium of this genus— Bacillus thuringiensis— 
originally discovered in Germany in 1911 in the province of Thuringia, where it was found to 
cause a fatal septicemia in the larvae of the flour moth. This bacterium actually kills by 
poisoning rather than by disease. Within its vegetative rods there are formed, along with 
spores, peculiar crystals composed of a protein substance highly toxic to certain insects, 
especially to the larvae of the mothlike lepidopteras. Shortly after eating foliage coated with 
this toxin the larva suffers paralysis, stops feeding, and soon dies. For practical purposes, the 
fact that feeding is interrupted promptly is of course an enormous advantage, for crop damage 
stops almost as soon as the pathogen is applied. Compounds containing spores of Bacillus 
thuringiensis are now being manufactured by several firms in the United States under various 
trade names. Field tests are being made in several countries: in France and Germany against 
larvae of the cabbage butterfly, in Yugoslavia against the fall webworm, in the Soviet Union 
against a tent caterpillar. In Panama, where tests were begun in 1961, this bacterial insecticide 
may be the answer to one or more of the serious problems confronting banana growers. There 
the root borer is a serious pest of the banana, so weakening its roots that the trees are easily 
toppled by wind. Dieldrin has been the only chemical effective against the borer, but it has now 
set in motion a chain of disaster. The borers are becoming resistant. The chemical has also 
destroyed some important insect predators and so has caused an increase in the tortricids — 
small, stout-bodied moths whose larvae scar the surface of the bananas. There is reason to 
hope the new microbial insecticide will eliminate both the tortricids and the borers and that it 
will do so without upsetting natural controls. 

In eastern forests of Canada and the United States bacterial insecticides may be one important 
answer to the problems of such forest insects as the budworms and the gypsy moth. In 1960 
both countries began field tests with a commercial preparation of Bacillus thuringiensis. Some 
of the early results have been encouraging. In Vermont, for example, the end results of 
bacterial control were as good as those obtained with DDT. The main technical problem now is 
to find a carrying solution that will stick the bacterial spores to the needles of the evergreens. 
On crops this is not a problem— even a dust can be used. Bacterial insecticides have already 
been tried on a wide variety of vegetables, especially in California. Meanwhile, other perhaps 
less spectacular work is concerned with viruses. Here and there in California fields of young 
alfalfa are being sprayed with a substance as deadly as any insecticide for the destructive alfalfa 
caterpillar— a solution containing a virus obtained from the bodies of caterpillars that have died 
because of infection with this exceedingly virulent disease. The bodies of only five diseased 
caterpillars provide enough virus to treat an acre of alfalfa. In some Canadian forests a virus 
that affects pine sawflies has proved so effective in control that it has replaced insecticides. 
Scientists in Czechoslovakia are experimenting with protozoa against webworms and other 
insect pests, and in the United States a protozoan parasite has been found to reduce the 
egglaying potential of the corn borer. To some the term microbial insecticide may conjure up 
pictures of bacterial warfare that would endanger other forms of life. This is not true. In 

contrast to chemicals, insect pathogens are harmless to all but their intended targets. Dr. 
Edward Steinhaus, an outstanding authority on insect pathology, has stated emphatically that 
there is 'no authenticated recorded instance of a true insect pathogen having caused an 
infectious disease in a vertebrate animal either experimentally or in nature.' 
The insect pathogens are so specific that they infect only a small group of insects— sometimes a 
single species. Biologically they do not belong to the type of organisms that cause disease in 
higher animals or in plants. Also, as Dr. Steinhaus points out, outbreaks of insect disease in 
nature always remain confined to insects, affecting neither the host plants nor animals feeding 
on them. Insects have many natural enemies— not only microbes of many kinds but other 
insects. The first suggestion that an insect might be controlled by encouraging its enemies is 
generally credited to Erasmus Darwin about 1800. Probably because it was the first generally 
practiced method of biological control, this setting of one insect against another is widely but 
erroneously thought to be the only alternative to chemicals. In the United States the true 
beginnings of conventional biological control date from 1888 when Albert Koebele, the first of a 
growing army of entomologist explorers, went to Australia to search for natural enemies of the 
cottony cushion scale that threatened the California citrus industry with destruction. As we 
have seen in Chapter 15, the mission was crowned with spectacular success, and in the century 
that followed the world has been combed for natural enemies to control the insects that have 
come uninvited to our shores. In all, about 100 species of imported predators and parasites 
have become established. Besides the vedalia beetles brought in by Koebele, other 
importations have been highly successful. A wasp imported from Japan established complete 
control of an insect attacking eastern apple orchards. Several natural enemies of the spotted 
alfalfa aphid, an accidental import from the Middle East, are credited with saving the California 
alfalfa industry. Parasites and predators of the gypsy moth achieved good control, as did the 
Tiphia wasp against the Japanese beetle. Biological control of scales and mealy bugs is 
estimated to save California several millions of dollars a year— indeed, one of the leading 
entomologists of that state, Dr. Paul DeBach, has estimated that for an investment of 
$4,000,000 in biological control work California has received a return of $100,000,000. 
Examples of successful biological control of serious pests by importing their natural enemies are 
to be found in some 40 countries distributed over much of the world. The advantages of such 
control over chemicals are obvious: it is relatively inexpensive, it is permanent, it leaves no 
poisonous residues. Yet biological control has suffered from lack of support. California is 
virtually alone among the states in having a formal program in biological control, and many 
states have not even one entomologist who devotes full time to it. Perhaps for want of support 
biological control through insect enemies has not always been carried out with the scientific 
thoroughness it requires— exacting studies of its impact on the populations of insect prey have 
seldom been made, and releases have not always been made with the precision that might 
spell the difference between success and failure. 

The predator and the preyed upon exist not alone, but as part of a vast web of life, all of which 
needs to be taken into account. Perhaps the opportunities for the more conventional types of 
biological control are greatest in the forests. The farmlands of modern agriculture are highly 
artificial, unlike anything nature ever conceived. But the forests are a different world, much 
closer to natural environments. Here, with a minimum of help and a maximum of 

noninterference from man, Nature can have her way, setting up all that wonderful and intricate 
system of checks and balances that protects the forest from undue damage by insects. 
In the United States our foresters seem to have thought of biological control chiefly in terms of 
introducing insect parasites and predators. The Canadians take a broader view, and some of the 
Europeans have gone farthest of all to develop the science of 'forest hygiene' to an amazing 
extent. Birds, ants, forest spiders, and soil bacteria are as much a part of a forest as the trees, in 
the view of European foresters, who take care to inoculate a new forest with these protective 
factors. The encouragement of birds is one of the first steps. In the modern era of intensive 
forestry the old hollow trees are gone and with them homes for woodpeckers and other tree- 
nesting birds. This lack is met by nesting boxes, which draw the birds back into the forest. Other 
boxes are specially designed for owls and for bats, so that these creatures may take over in the 
dark hours the work of insect hunting performed in daylight by the small birds. 
But this is only the beginning. Some of the most fascinating control work in European forests 
employs the forest red ant as an aggressive insect predator— a species which, unfortunately, 
does not occur in North America. About 25 years ago Professor Karl Gosswald of the University 
of Wurzburg developed a method of cultivating this ant and establishing colonies. Under his 
direction more than 10,000 colonies of the red ant have been established in about 90 test areas 
in the German Federal Republic. Dr. Gosswald's method has been adopted in Italy and other 
countries, where ant farms have been established to supply colonies for distribution in the 
forests. In the Apennines, for example, several hundred nests have been set out to protect 
reforested areas. 'Where you can obtain in your forest a combination of birds' and ants' 
protection together with some bats and owls, the biological equilibrium has already been 
essentially improved,' says Dr. Heinz Ruppertshofen, a forestry officer in Molln, Germany, who 
believes that a single introduced predator or parasite is less effective than an array of the 
'natural companions' of the trees. 

New ant colonies in the forests at Molln are protected from woodpeckers by wire netting to 
reduce the toll. In this way the woodpeckers, which have increased by 400 per cent in 10 years 
in some of the test areas, do not seriously reduce the ant colonies, and pay handsomely for 
what they take by picking harmful caterpillars off the trees. Much of the work of caring for the 
ant colonies (and the birds' nesting boxes as well) is assumed by a youth corps from the local 
school, children 10 to 14 years old. The costs are exceedingly low; the benefits amount to 
permanent protection of the forests. Another extremely interesting feature of Dr. 
Ruppertshofen's work is his use of spiders, in which he appears to be a pioneer. Although there 
is a large literature on the classification and natural history of spiders, it is scattered and 
fragmentary and deals not at all with their value as an agent of biological control. Of the 22,000 
known kinds of spiders, 760 are native to Germany (and about 2000 to the United States). 
Twenty-nine families of spiders inhabit German forests. To a forester the most important fact 
about a spider is the kind of net it builds. The wheel-net spiders are most important, for the 
webs of some of them are so narrow-meshed that they can catch all flying insects. A large web 
(up to 16 inches in diameter) of the cross spider bears some 120,000 adhesive nodules on its 
strands. A single spider may destroy in her life of 18 months an average of 2000 insects. A 
biologically sound forest has 50 to 150 spiders to the square meter (a little more than a square 
yard). Where there are fewer, the deficiency may be remedied by collecting and distributing the 
baglike cocoons containing the eggs. 'Three cocoons of the wasp spider [which occurs also in 

America] yield a thousand spiders, which can catch 200,000 flying insects,' says Dr. 
Ruppertshofen. The tiny and delicate young of the wheel-net spiders that emerge in the spring 
are especially important, he says, 'as they spin in a teamwork a net umbrella above the top 
shoots of the trees and thus protect the young shoots against the flying insects.' As the spiders 
molt and grow, the net is enlarged. 

Canadian biologists have pursued rather similar lines of investigation, although with differences 
dictated by the fact that North American forests are largely natural rather than planted, and 
that the species available as aids in maintaining a healthy forest are somewhat different. The 
emphasis in Canada is on small mammals, which are amazingly effective in the control of 
certain insects, especially those that live within the spongy soil of the forest floor. Among such 
insects are the sawflies, so-called because the female has a saw-shaped ovipositor with which 
she slits open the needles of evergreen trees in order to deposit her eggs. The larvae eventually 
drop to the ground and form cocoons in the peat of tamarack bogs or the duff under spruce or 
pines. But beneath the forest floor is a world honeycombed with the tunnels and runways of 
small mammals— whitefooted mice, voles, and shrews of various species. Of all these small 
burrowers, the voracious shrews find and consume the largest number of sawfly cocoons. They 
feed by placing a forefoot on the cocoon and biting off the end, showing an extraordinary 
ability to discriminate between sound and empty cocoons. And for their insatiable appetite the 
shrews have no rivals. Whereas a vole can consume about 200 cocoons a day, a shrew, 
depending on the species, may devour up to 800! This may result, according to laboratory tests, 
in destruction of 75 to 98 per cent of the cocoons present. 

It is not surprising that the island of Newfoundland, which has no native shrews but is beset 
with sawflies, so eagerly desired some of these small, efficient mammals that in 1958 the 
introduction of the masked shrew— the most efficient sawfly predator— was attempted. 
Canadian officials report in 1962 that the attempt has been successful. The shrews are 
multiplying and are spreading out over the island, some marked individuals having been 
recovered as much as ten miles from the point of release. 

There is, then, a whole battery of armaments available to the forester who is willing to look for 
permanent solutions that preserve and strengthen the natural relations in the forest. Chemical 
pest control in the forest is at best a stopgap measure bringing no real solution, at worst killing 
the fishes in the forest streams, bringing on plagues of insects, and destroying the natural 
controls and those we may be trying to introduce. By such violent measures, says Dr. 
Ruppertshofen, 'the partnership for life of the forest is entirely being unbalanced, and the 
catastrophes caused by parasites repeat in shorter and shorter periods. ..We, therefore, have to 
put an end to these unnatural manipulations brought into the most important and almost last 
natural living space which has been left for us.' . . . 

Through all these new, imaginative, and creative approaches to the problem of sharing our 
earth with other creatures there runs a constant theme, the awareness that we are dealing 
with life— with living populations and all their pressures and counter- pressures, their surges 
and recessions. Only by taking account of such life forces and by cautiously seeking to guide 
them into channels favorable to ourselves can we hope to achieve a reasonable 
accommodation between the insect hordes and ourselves. 

The current vogue for poisons has failed utterly to take into account these most fundamental 
considerations. As crude a weapon as the cave man's club, the chemical barrage has been 

hurled against the fabric of life— a fabric on the one hand delicate and destructible, on the 
other miraculously tough and resilient, and capable of striking back in unexpected ways. These 
extraordinary capacities of life have been ignored by the practitioners of chemical control who 
have brought to their task no 'high-minded orientation', no humility before the vast forces with 
which they tamper. The 'control of nature' is a phrase conceived in arrogance, born of the 
Neanderthal age of biology and philosophy, when it was supposed that nature exists for the 
convenience of man. The concepts and practices of applied entomology for the most part date 
from that Stone Age of science. It is our alarming misfortune that so primitive a science has 
armed itself with the most modern and terrible weapons, and that in turning them against the 
insects it has also turned them against the earth. 

When you read SILENT 
SPRING you will know 
why Justice William O. 
Douglas called it "THE 



"A smashing indictment 
that faces up to the disastrous 
consequences, for both nature 
and man; of the chemical 
mass-warfare that is being 
waged today indiscriminately 
against insects, weeds and 
fungi ..." 
-New York Herald 

'The thing to remember . . . 
is that the author is not an 

alarmist but a trained, 
meticulously scrupulous 

scientist, who shuns 
publicity and controversy 
but whose findings were 
too catastrophic to keep to 



CoverS. Neil Fujita